Why does players don't want a rematch? There should be a best of 3 or 5 or 7 in this game.

Because they don't owe you anything.
When you play a game with someone in the lobby they are not bound by any rules to accept a rematch.

People don't care about the score. They just wanna play whomever. Not a good reason for a rematch.
Think about what happens right before you want that rematch. Did you just get annihilated and resigned in the middlegame? Are you clearly about to get mated? Forget it.
I think I speak for a lot of people when I say this, but correct me if I am wrong. I think we like being challenged, as it's not only what makes us better at the game, but it's far more satisfying to play (and win) against someone who can really challenge us. What is the point of a rematch when you showed your skills to be unsatisfying? Free rating points? If I want a higher rating, I'll just play arenas. Is my self-esteem that shitty that I just want to beat someone/want my rating to go up?
What is the point of playing you again? That is the question you have to answer. Are we friends? Are you an interesting player? Did we connect in the chat perhaps? if not, then I have no reason to play you again.

The number of matches should be exactly:

42

Empety

this also means that they have some work to do or need to go somewhere . when i dont accept rematches becuase of the same reason , they say im a coward

Why don't people want pineapple in their pizza? Pineapple should be a compulsory ingredient in all pizzas.

#8 guys please all but not pineapple or similar. Or ill do a massacre

#3 how can you be so proud on beating a player that is much lower rated than you? And I'm not sure that your post respect the forum etiquette in addition...