Etiquette

Good Habits

Respect your opponent's ability
Thanking your opponent after the game
Playing a game until the end - 1 disk is better than 0 disks, and unlike chess the game will end soon.
It is better to dip your fingers in the coffee than to try to drink the discs.

Bad Habits

Naming all your excuses for losing
Taking back a move
Dangling a disc above the board while thinking
Equating Othello skill with intelligence
Telling your opponent that she/he played very well while she/he only got 2 discs
Compare Othello with chess
Get angry
Asking someone in the audience the help flipping if your flag is likely to fall
Answer the crappy play with diabolic laughter
Hitting your opponent on the head with a wooden stick is vulgar style.
Singing when playing
Throwing the board against the wall denting the wall and the board prior to uppercutting your opponent
Accidently getting a disc stuck up your nose and then having to get it removed in the emergency room
Tapping with your feet on the ground
Constantly ticking with your stone on the table
Pretending you don't care about your own game and go walking around and spectate other games
Throwing a stone up and catch it, over and over again.
Replaying the opening of your own game with the person next to you, using the table and the remaining discs.
Sighing so heavily that your opponent can smell what you had for lunch
Commenting on your match very loudly as soon as it's finished, regardless of whether the other matches are finished
Putting the discs to your mouth while planning your next move
Dressing like a $50 hooker in order to distract your opponents

Bad internet habits:

Communicating with idiotic abbreviations
Rating paranoia
Aborting the game / Resigning repeatedly
Playing online more than 6 hours per day (if in question about this, ask your family)
Using Zebra or other software to find the moves for you
Accusing anyone who knows your opening further than 7 moves of using Zebra
Registering multiple nicks