NpPro93 said:
Every romantic comedy ever:
1) Guy meets girl
2) Guy tells small lie to get girl to like him
3) Guy and girl fall in love; lie escalates
4) Girl finds out about lie; big fight and break up
5) Sad montage
6) Guy tells the girl how much he loves her at a dramatic moment in an usual place and they get back together
The gender roles can be reversed, and it works for almost any movie, including good ones like Wedding Crashers.
What about Annie Hall, When Harry Met Sally, High Fidelity or (500) Days of Summer?
Illusio said:
The protagonist gets betrayed by someone, oh wow that's something new.
Not really a cliche. Its a common plot device, but that doesn't make it a cliche. It would be like saying "Some guys have to fight in a war... what a boring cliche!", "a man has to save his loved ones... Cliche!" or "the protagonist is in a situation...Seen it a million times before".
Also, if it didn't happen, you would probably be saying "Everyone in movies is trustworthy. Noone is ever looking out for themselves over their friends, noone has ulterior motives for working together, etc."
Obviously, betrayal can be done very badly in movies, it can be done in a cliched way, or badly crowbarred into the story. But it can also be done very well (The Good, the Bad and the Ugly, Resevoir Dogs, Hero, The Maltese Falcon).