I confess I don’t get the outrage I have been exposed to regarding:
[ul]
[li]Cell phone use in public[/li][li]Other people’s driving (judging from the SDMB people are quite divided about a number of perceived offenses)[/li][li]Elbows on the table[/li][li]Cupping my hand at my ear in order to hear better[/li][li]Certain non-verbal communication (shrug, squint, furrow, eye-roll, etc.)[/li][/ul]
-Unsolicited Sales Calls
-Swearing
-The responsible use of any mind or mood altering chemical
-The use of any kind of tobacco
-Jesus talk in non churchy settings
-Tattoos
Forgetting my name / getting my name wrong. Nobody is worse than me at names. Don’t sweat it.
Jokes about race or religion dont bother me much. Lots of other things already mentioned. Drug use doesn’t bother me unless its harmful to others.
I forgot homeless people. I worked with them for so long that I don’t take anything that they do personally. I say just what I think, laughed at them, they yelled at me and I yelled at them and there is no conversation too weird for me to have and enjoy with a crazy person on the street. I don’t mind being panhandled, I’m used to the stink and as long as they don’t get close enough to give me bugs I barely notice it. Some of them can annoy the shit out of me but the stuff that they do is a reflection of how messed up they are and not about how they feel about me, so offending me isn’t really possible.
Holy cow, I couldn’t agree with this more. I know people who are devastated by brusqueness. Why? Get to the point is literally my motto.
At work, I have to balance customer service and sales. I do very well, because I have mastered the art of ‘short and sweet’. It allows me to get on to the next customer quickly, which means another opportunity for sales. My co-workers marvel at this, and I am very proud of it. The trick is to be brusque with some honey on it, but I don’t care if any honey comes on the brusqueness that someone serves to me. Just get to the point.
Something else that never bothers me, but I notice people are bothered by it, is when someone is mad at me, or not speaking to me, or whatever. I am always thinking, “they’ll get over it”. Half the time, I don’t even know they are mad untill they finally come out and say it, (Nzinga, I am not speaking to you because you hurt my feelings about…) or whatever. I just apologize and be done with it.
It is funny, because I often imagine myself buddies with people that can’t stand me. Ha! Someone finally pullls my coat sometime, “Nzinga, you smile and speak to that girl every day, and she can’t stand you!”
Just the other day someone was asking about my photo collection of the “mind your manners” posters that the Tokyo subways put up. most of them seemed like straightforward courtesy: watch where you swing your bags, one seat per person, don’t act like a drunken moron, etc.
One of them stood out from the rest, though: don’t put on makeup in the train. 
What’s supposed to be so bad about that? I question the intelligence of holding a pencil point next to your eyeball in a moving vehicle, but so long as I don’t get eye shadow (or eyeball) smeared on my shirt, why would I care?
Breastfeeding in public, with or without a blanket. Breastfeeding toddlers.
Other people’s bad driving. I’ve used my horn maybe twice since I got my license, and both times it was an attempt to warn someone who was about to hit me. I’m mellow yellow when I’m driving, nothing really bothers me. Cut me off, change lanes, drive the speed limit in the left lane, don’t really care. I also don’t get into the “merge debate”. Although I usually get in the merging lane early rather than maintaining 2 lanes until the merge point, It doesn’t bother me when people do otherwise.
Telemarketers. I know some people that get highly upset about this, but I don’t give a swut. As soon as I realize it’s a telemarketer on the phone, I give a firm but polite “I’m sorry, I’m not interested”, and hang up. It takes maybe 10 seconds. Getting steamed up about it and ranting to everyone you know takes a lot longer.
Table manners. Eat with your fingers, put your elbows on the table, use the salad fork to eat your steak, as long as your not spraying food everywhere as you talk it doesn’t bother me. Not that I do any of those things, it just doesn’t bother me when other people do. However, if you attempt to take food from my plate without asking, I will stab you with my fork.
I came a little late to this thread, but yeah. Jeez it gets bad sometimes, don’t try to talk to me with mashed potatoes in your mouth.
Smacking of the gums? You can’t refrain from that for a few minutes? Actually don’t talk to me again.
Now I will ladle soup straight towards my mouth. I Don’t care if other countries find it cultured or not.
Brusqueness. Getting straight to the point is good, even if that point is phrased in a less than charming manner.
Unsuprisingly, inappropriate gooey sweet Happy-Joy-Joy-Sunshine tones and “spin” piss me right off.
Just spit it out, dammit. 
Racist / bigoted / anti-gay / anti-anything-I-am-or-feel-shouldn’t-be-discriminated-against jokes don’t bother me as long as they’re funny. They’re just rarely funny. But the funniest gay-bashing joke I ever heard was told to me by a homosexual friend.
It was mentioned upthread, but I’ll say it again. Tattoos. A lot of people don’t like them, some are offended (even to the point of threadshitting). I love’em. I love mine, I love other peoples. I can stare at them all day.
Lid off the toothpaste? No problem.
One of the downsides, I suppose to taking a linguistics course (Just enough to be dangerous, ya’ll!) is that I can rationalize my profanity. Really, they are words, pretty sure you’ve heard them all a kabillion times. Can a cuss word really throw you in that big a tizzy?
What you have in your yard/color of your house/anal retentive lawn. It is your property, that you paid for. As long as it doesn’t stink, grow mosquitoes or hide bodies, not only do I not care, I probably won’t notice. Yes, I do respect that my neighbor is outside neurotically putting fake flowers in her beds and harassing the hell out of her grass, so I try to keep it under control, but really, it’s her yard, I don’t care. Corollary, I also like good fences. And yes, I’m moving to the country.
Toilet lid up when it should be down, or vice-versa? No problem. I can move it.
Other people too talkative? No problem. I can either tune them out or tactfully excuse myself from further exposure.
Racist, dirty or homophobic jokes? No problem. I’ve heard some of the best from members of the subgroups being “attacked.”
Catty office gossips? No problem. I can ignore them easily.
Nib-nose neighbors or guilt-tripping relatives? Ditto and ditto.
Couples in which one person is very young and the other is very old? No problem. If no law is broken and they love each other, God bless 'em.
Telemarketers? No problem. A polite but firm “No, thanks” and I hang up. Works every time.
Yeah, I DO NOT get this whatsoever. Luckily my wife has never so much as commented on it, but I know couples who fight like two cats with their tails tied together about it. If lifting or lowering a toilet seat is an issue big enough for you to fight about, you have waaaaay bigger problems, IMO.
-Forgetting to send me thank you notes: If I didn’t get you something only to obligate you thank me for it in writing, therby wasting not only paper, but my time and yours. If you must, write an email. Ditto for Christmas cards
-Dinners where no dessert is served: I actually prefer these. I hate having to choke down some sugar-filled mess that’s bad for me just because I’m being polite.
-Your monetary gift being less than your sister’s/last year’s/etc: I don’t compare, nor do I remember.
-Others disciplining my child: If he’s being a beast, please do tell him so and save me the trouble.
-People who don’t suscribe to a faith: I’m a believer, but I don’t care if you are. Seriously.
-Spanking, meat-eating, fur-wearing: Some I do, some I don’t, but I don’t get on anyone for any of them.
Everyone forgetting my birthday. No card, no mention, no calls, no sweat. I won’t cry about it or even have a bad day over it. Chances are I won’t even remember it’s my birthday either. And if you do remember it’s not going to magically make my day. I’ll probably say thanks and go about my business.
Nails on a chalkboard sound. Doesn’t bug me in the slightest.
Stores uptight return/exchange policies. It’s their store they can run it however they like. If I can’t handle the policy I won’t shop there. No one’s holiding a gun to my head. No sense bitching at a customer service gal or a manager, they didn’t make the policy.
Redwing, I think we would be good friends 
I’ll add:
Brutal honesty. I hate having to guess the hidden meaning of your words, just tell me! I’m not going to get my panties in a knot if you come out and say “I’m pissed that you didn’t wash the coffee pot” and I doubt I’m going to figure out that that’s the problem if you just huff and puff around the office.
Don’t know if people find weeds and leaves “offensive”, but they don’t bother me at all. It’ll all die and dry up eventually.
Just about everything.