Not necessarily in a bad way…
People think I’m nutty because:
–I shop for shoes mostly online even though there are multiple shoe outlets near my house
–I like to drink tonic water by itself
–I like cold Brussels sprouts with nothing on them
–I saw The English Patient in the theatre–three times.
–I put Tabasco on my cottage cheese
–I frequently go on charter bus trips with a bunch of senior citizens-
What qualifies YOU for the subjective nuthouse?
Oh, jeez.
Perhaps it’s the fact that I react to things that have tentacles and large, hairy insects in the same way an 8 year old girl would react to a freshly fluffed kitten. The Great Cthulhu, for example, makes my heart happy in a way that no mortal should ever know.
Maybe it’s the joy I take in performing my amoeba impression? (blanket required, obviously.)
The fact that on Deep Space 9, Odo is my favorite character because he liquefies on a regular basis into a gelatinous goo and sleeps in a bucket?
Or how about the giant slugs we encountered laying on the sidewalk in Florida, which I immediately photographed and gently stroked with my finger just to get them to wiggle around a bit?
The thing that most people find disturbing is that these things genuinely bring me a sense of childlike glee. When I’m feeling depressed, I look at pictures of seaslugs and it actually succeeds in cheering me up, because HOW CAN YOU BE SAD when there are seaslugs and tubeworms in the world? 
In short, there is no one reason. My entire existence is the reason. And I am so totally cool with that.
I can’t spobknuckle hatstand think of any.
This is completely awesome.
As for me, I have a maniacal laugh (which resounds frequently through whatever building I find myself in) and a tendency to do an Igor impression, which I perfected during grocery store trips with my mother when I was made to get various items for her and would go after them, saying, “Yes, master, a lettuce for my master!”
I also duel people with animal crackers.
Heh. that’s actually been a bit of a thing in my family too. I forget where and when it started, but if my sister or I have to turn on the TV or something, we’ll do the Igor voice with, “May I pull ze svitch NOW, Master?”
When my dad was younger (in his 60s) and more agile, he had a patented gargoyle impersonation which involved sitting on the corner of a table, leaning forwards, and pulling grotesque faces. I guess you had to be there, but it was brilliant.
Because they can see how how much effort I put into it. Not just phoning it in, not just nibbling at it around the edges, but claiming it as my own and reinventing it every day I’m out there.
Call me old-fashioned and out of step., but I just feel the fans deserve no less. And yes, it helps if you’re just a little bit crazy.
I like buttermilk.
many reasons, but the essential ones are
because I’m a white girl, and if I like a rap song, I know all of the words and rap along loudly and quite skillfully.
because my coworker and I go back and forth singing Salt-n-Pepa songs (esp. “Push It”) at work when it gets too quiet.
ooh baby BAY-beh! ooh baby BAY-beh!
I like frying up chunked rhubarb with mince and onions. I’m apparently the only person on the planet who does this, and it makes people move away from me when they learn of it.
More for me, anyway. cackling larf 
I get embarrassed for fictional people on TV or in movies, and have to cover my eyes or leave the room when they do something that would embarrass me. This makes watching some types of comedies difficult, and usually results in a family member yelling at me to get back in the room and sit down.
Haha! I would fit right in.
Because I thought living in Beirut, Lebanon, was as close to Heaven as one can get on earth, and would go back in a heartbeat.
I have a really odd sense of humor and sometimes think things are funnier if you never break that it’s a joke and just keep on keeping on like everything is just fine. Keeps people on edge, that does. Mostly they laugh, but somehow nervous laughter is my favorite. I’m known for joking around all the time, but sometimes you have to let them think you’re not kidding.
I’m pretty sure all of my coworkers think I’m batshit insane.
Take a look at this. It has literally been giving me nightmares. I need to pass him on to someone else that appreciates him.
I do something a bit different with game shows: I scream at contestants : “HOW COULD YOU NOT KNOW THAT?!”
I don’t know why they never listen to me when I shout out the answers.
<checks profile> …damn! She’s married already.
If I can dissolve him with my own bodily secretions, will you go out with me?
Hardly the defining reason, but as an example, the fact that I’m absolutely tickled to live in a place that’s been described with the following:
“The southeastern knob of Arakawa, Minami Senju, has long suffered from issues of identity, in some part because of its northeastern orientation vis-a-vis the perspective of Edo rulers. In Buddhist belief, northeast is kimon, or the direction from which evil forces come. As a result, at least in part, Minami Senju came to include a corner of the impoverished day-laborers’ warren of Sanya; the Nagekomi-dera at Jokanji, a temple where Yoshiwara prostitutes were interred; the Edo execution grounds known as Kozukappara where an estimated 200,000 criminals were punished with decapitation, burning, or even crucifixion; and what is still locally known as Kotsu Dori (“Bone Avenue”), where severed heads of the executed were displayed on poles.”
See the "Which Geek Are You? thread.
I am a moderator on the SDMB.
'Nuff said.
Cuz I have one of these hats and wear it happily in public (the scarfits).