A list of items to be negotiated before the game.

It would be good to have a list of items to be negotiated before the game, such as when resignation will occur, what saying "good game" means after the game, what saying "Good Luck" before the game means, whether conditional moves will be considered arrogant, which are better pancakes or waffles, and perhaps, who was the best player of all time.

Have I forgotten anything?

All of your planned vacations for the next 12 months.

How quickly you plan to move, with advance notice in writing if this is going to be changed. Opponent must agree to change, also in writing.

also if your opponent is going to change his or her screen name and not quite as important--avatar at any point during the game.

If they are the type of person to take real vacations bug log in to read message boards, they should tell you. And you have the option of blocking this behavior.

When and how many times it's acceptable to offer a draw could be one.  Along with best player ever we could clear some other things up like which is preferable, knights or bishops, how exactly en passant works, how ratings work, how the time control works, whether you can have more than 1 queen, and if stalemate really is a draw.

Will the players use opening databases or are players required to remember stuff?

1. Whether drawing by repetition means you're a gutless weasel.

2. How quickly after the game one may publish it to the forums (complete with derogatory remarks) and whether or not one should include the hapless victim's real username.

3. How many minutes one is allowed to be showing online before a move is expected in a 3 day-per-move game.

What kind of music, if any, the two parties will listen to during the game. If agreement cannot be reached the game is aborted. 

Will you let time run out rather than resign?

at what moment of time the engine starts to kick in or will be switched off.

Whether e4 or d4 will be played.

What the 50 move rule means, whether it will be observed or will play be allowed to continue forever?

If chat is permitted, are vwls optional?

What kind of music they listen to (dont want the humiliation of being mated by someone who listens to 'rap')

pro-life or pro-choice?

Will you be resigning quickly in order to get your preferred color in the next game?

Wait, why should anything be agreed ahead of time? As long as I play within the confines of the implicit contract created upon the creation of the game, I am 100% sportsmanlike, and nothing you say or do can change this. Yo.

yeah yo

the winner decides it all

 Unfortunately, if this was implemented, the game would never start.