Worst Thing To Do On Your First Move

Say $!?%#@! when your opponent plays e4

Numbering 400 when this thread is just in post #300

Didn't you mean post #305?

Well you numbered 399

Get a tattoo of Harry the h-pawn with the word stupid under while your opponent beats you with Harry the h pawn

After 1.Nh3 hit your head with the king saying,"Why anybody didn't teach me this opening ?"And resign.

Have Papa's Umbrella Key Ear / Puke and also eat Pancake Omlete Ogre Pee / Poop.

Read some good books on chess psychiatry

🏃 

A few things can't be on the list as they have no direct or indirect impact on the outcome of the game, especially during an online game. For example your number 2. Fart ... Neither does that irritate or distract your opponent, nor is this a real advantage / disadvantage for you.

Your idea with the question was great but u shot your only bullet with number 1.

Forget you were playing a GM and start playing like you were playing a 100 rated player

Move aimlessly 

Starters at your opponent's beard and lose on time

I mean stare at your opponent's beard

Have a heart-attack as a result of a nervous breakdown.

Eat Pizza at the board

Play "Wrecking Ball" on your phone.