Different

Why cash games are different from MTT tournament?? People play cash games differently why is that❓

Unlike MTTs, you can quit a cash game at any time and collect your winnings. This is convenient because you don't have to wait hours for the tournament to end. The main reasons players come to MTTs are the big wins and unforgettable experiences.

Cash games: Each chip equals real money (There's no "pressure" to survive, no bubbles or prize jumps, only making decisions matters + pure EV).

MTTs: Chips don't have linear value (Survival can be more important than winning a pot, there are bubbles, prize jumps, and ICM, which changes preflop range and aggression).

First of all, cash games are harder for many players because chips = real money, and that pressure affects their decisions — for example, whether to call with a medium-strength hand. In tournaments, players will often call automatically, especially early on.
Second, cash games usually have stronger opponents, so many people prefer not to get involved too much so they don’t bust their bankroll quickly.

As others have said, in cash games a dollar won or lost is a dollar won or lost, and each hand is independant of the previous ones. In tournaments there are tactical considerations, because the goal is to outlast other players, until its down to the final two. So sometimes in tournaments its better to pass on a marginal spot and wait for someone else to bust.

In tournaments the blinds also go up, which tend to make the effective stack size shorter. In a typical online cash game you need to be good at 100BB poker. In tournaments you need to master different stack sizes, but most of the play happen with an effective stack size of 40BB or less depending on the speed of the tournament.