One thing I've noticed with supposedly weird people is that they'll do little things to amuse themselves and not care what everyone else thinks of it. Like they may say a comment out loud that will entertain them to hear, but will offend or confuse everyone else. They may revert to this kind of behavior when they're bored or have nothing else to do. Sometimes it's almost like they have a little in-joke with themselves. At other times they get entertainment simply from acting strange. The obvious drawback is that outside of their own little world other people think they're acting odd.
Having too many esoteric thoughts, knowledge, and experiences in your head.
Sometimes people are seen as weird because they've spent hours and hours accumulating non-typical knowledge and experiences. If they're having a conversation and want to relate a point of your own, they're more likely to come up with something that seems bizarre and out of place to most people, because they don't have as much 'typical' material to draw from. For example if everyone is joking around about sex, they may mention something they read about the peculiar mating habits of barnacles. Nothing wrong with being interested in that topic, but it's a lot more random than what most people expect to hear. If your brain is pre-loaded with nothing but 'weird' things then you can't help but let it come out in conversations, like I do, always skipping around subjects, making it quite hard for a proper conversation.
Being Square or old-fashioned is fine, living like an old man but to some this behavior may seem weird. Normal* people found the ones being ideologically isolated (listening to Frank Sinatra and never heard modern music but saying new music is crap and thinking the old fashioned or stubborn way). This is mainly caused by their own experiences when they were young. I knew two brothers (One still have some hair and the another one is bald) who were frozen in time since 1959, they still trying to maintain the Elvis Presley's 50s hairstyle. No matter what times did you live through, I personally think it is important to keep up with the age. Just being different from the norm in some way.
I've never heard anyone say, "Look at that weird jock", but you'll often hear, "Look at that weird Goth kid." To a large degree Goths are seen as weird, and jocks seen as normal, because one subculture is way more common than the other. Sure, some people would argue that Goths are weird in other ways as well, but I think it's all pretty subjective. Many people will be seen as weird simply for dressing very differently, having an crazy hobby, having a unique way of looking at the world, or having opinions that aren't entirely mainstream (in this case I will explain with more detail in the following). This is the variety of weirdness that many people probably won't want to change took much, or only make slight adjustments to.
Written by Winston.
This point and the ones below cover behaviors that are more objectively problematic. People often get called weird when they make a lot of social mistakes. They're seen as strange because their behaviors is not what others are expecting. People may also assume a person's social errors are symptoms of a more core oddness.
Not making enough eye contact? Weird.
Laughing without reason?Weird.
Standing too close? Weird.
Speaking in a funny voice? Weird.
Was asked a question where people normally give a canned response and said something out of left field instead? Weird.
Disclosing too much personal information at a time when it's not so appropriate? Weird.
Brought up a gross subject during a meeting? Weird.
It's four in the morning and he switched on the music and started dancing? Weird.
Seemed really uncomfortable and stammered out two-word reply when I said hello?
Maybe just shy, possibly weird as well.
Being really quiet? Again, many people could see this behavior as a sign of shyness, but some would also label it as weird too.
I could go on and on. Of course just improving your social skills will correct this problem.
Written by Winston.