A bad habit.
I'm going to give you a moment to recover from that groaner before we continue....
So, habits, we all have them. They are those idiosyncrasies we commit without realizing it. What causes them? Well a number of things; stress, positive re-enforcement, learned behavioral patterns at random, subconsious weaknesses, physical maladies that we accommodate for through subconscious action.... there are dozens if not hundreds of ways to pick up a habit.
Some of my habits? I talk with my hands. A lot. I talk with my eyebrows too; my friends say my eyebrows are like pole vaulters because they jump so high. Not only that I have the tendency to play with my goatee when I am thinking. The list goes on. And if you are human, you have tons of them too. Its just how we are.
So, the question is--if humans are habitual creatures and we are trying to make believable characters--why don't our characters have habits?
Easy habits are fun to write and extremely rewarding so chances are you will write those in more often than not--however I don't see these being tossed around like a salad either. To be very honest, I haven't read a single character on here brush their teeth. I guess we all have dentures. Males don't write about putting the lid down--I suppose technology advanced past that. We don't lock our doors before sleeping or take the keys out of the ignition on site either--I guess all the PC's are devoid of the need to worry about theft too and we rarely look both ways before cross the street.
How are we not all deceased again?
So, bad habits. I think we don't write them, more often than not, because we want our characters to be epic. My two, James and Akio are riddled with fault and flaws. James is a chain smoker and almost always inebriated to a degree. There is only one thread he has been in where the spacer wasn't waving around a bottle of booze and in pretty much every post, he has smoke leave his nose and or lips. Why? These are his bad habits. His grammar is terrible. Akio? He has a shattered psych. And I don't mean he is a psychopath; Multiple Personality Disorder, PTSD, depression, avoidance attachment patterns, and night terrors to name a few. They are equally balanced in their goods vs bads in character and in physicality.
To sum it all up, adding in those things about your character that my spiritual adviser called the "dark side" are good for your writing. By dark side, no I don't mean the dark side of the Force--Jedi rest easy and Sith stop cheering. I mean the parts of your character that you want so desperately to hide. Play off their weaknesses as well as their strengths. It makes for epic reading. Watch this:
"I ain't done nothing," George said.
Bleh. That is bland. Now, watch what happens we we add a few bad habits, eh?
"I ain't done nothing," George said biting his nails.
"I ain't done nothing," George said as he popped his knuckles.
"I ain't done nothing," George said as he pulled on a strand of his hair.
"I ain't done nothing," George said as he puffed on his cigarette (look familiar? You probably read one of James' posts. :D)
"I ain't done nothing," George said as he popped his neck.
Habits!! They are everywhere. Every has one. If you think you don't ask your friends or family to point some out. You'll be surprised what you find.
Now, go make your characters like the nuns and put a few habits on them!