When my parents began to lose their ability to function well in public here’s one which frequently came to mind after a flustered phone call from them about their latest confrontation with a ever more rapidly moving world:
Remember, in your haste, that sometimes people appear rude when they are, in fact, overwhelmed. Keep in mind that that dithering idiot in front of you is possibly someone’s parent and treat them the way you would want your parents to be treated. 
Things You Shouldn’t Have To Tell People
Hey, why can’t I edit my posts here?? (hoping this isn’t something You Shouldn’t Have To Tell Me… but it probably is … sighs)
Was going to edit mine to add “Do your Job so I don’t have to do it for you” and “Your driving a car and the lights have changed. Now is not the time to do your hair/change your station/adjust your rearview mirror”
Also, stand away from the doors while you wait. It blows my mind the way people will wait right smack in front of the doors and then look totally astonished when the doors open and there’s somebody in there wanting to get out.
Really, it’s the same principle as boarding public transportation, which may be why I get it and so many of my coworkers don’t - I was without a car for several years and used the bus during that time. But at least with the bus you have the advantage of a driver holding up a hand to tell boarders to wait while others get off.
There’s a five-minute window from the time you post where you can edit. After that, the edit button disappears forever for that post.
Please, even if it’s not a high-class restaurant, please don’t blow your nose at the table. *NOBODY *wants to hear that.
And if you miss when you toss something into the garbage can, do pick it up and try again. You don’t get penalized for a second attempt. I swear, I want to post a sign in the ladies’ room at work: Your mama doesn’t work here - pick up your paper towels!!!
Unless I indicate otherwise, take off your shoes in my house. I don’t care what you do at home.
I’ve found (through bitter experience) that posting snarky signs educating my co-workers about manners never ends well…
Thanks for the info 
Additionally, the phrase “get a room” is fairly common, there is a reason.
As past mega-threads have shown, this is not a “Thing You Shouldn’t Have To Tell People”. The two camps (shoes on and shoes off) are both pretty large and just about evenly divided.
Or hovering while spinning in a circle, as some ladies’ rooms I’ve seen (including work, sometimes) have indicated.
If someone is getting pee & blood on the seat, behind the seat, and on the floor in front of the toilet, how the hell are they not covered in it when they’re done?
I won’t do it, because people who are slobs won’t heed signs anyway. Which is why I haven’t posted a note on the crumbled pile of paper and plastic that was our office Christmas door decoration. I don’t know who dumped it on the floor just inside the door, but it’s been there at least 6 weeks. I hope the CO comes in and pitches a fit. Talk about unprofessional!! Bad enough we had that crap taped to the door in the first place…
As a call center worker, I implore everyone. Please, do not call me while you are doing your business on the toilet. I know that you may have to wait to talk to me and nature’s call may beckon, but please be considerate and call back after you are done.
Not much about my job gives me the shudders more than having a conversation with a client and hearing a loud flush during that conversation.
Which is something you shouldn’t have had to tell me. Good job!
If you’re keeping people on hold, for some undetermined period of time, then suck it up sweet cheeks!
Murphy’s law says I’ll be on hold for 20 mins, unless I go use the facilities, then, amazingly, mid business - you’ll take my call. Sorry about the flush but tough darts!
Trust me. I do. I would never be unprofessional in such a situation. But I still don’t want to hear you or anyone doing their business in the toilet while on the phone. Just let me know that you are indisposed, and when we can reach you. I’ll call you back.
If you’re walking down a busy sidewalk, don’t just stop! I’m looking at you, tourists and foreign language students. What’s with that?
Also, doorways in shops are crowded thoroughfares. Teenagers, do your talking while you’re walking.
And SHUT UP when you’re in the cinema, FFS.
“Your Birthday is Feb 14th?! Isn’t that Valentine’s Day?”
“Yes.”
“So your Birthday is on Valentine’s Day?”
“Yes.”
“Every year?”
::stab::
And while you’re at it, if you drip on the seat, please wipe it off.
Do not, upon pain of death and/or ass kicking, drive around in one of those damn “boom-boom” cars with the music so loud it rattles windows as you go down the street.
People should not have to be told that they don’t have the right to touch strangers without permission (unless adminstering life-saving aide, obviously). Not even if the stranger has pretty red or curly hair. Not even if the stranger is pregnant, not even if she’s having twins. It’s not okay to paw children you don’t know, and doing so to other adults is almost worse.