What's your favourite gaming mechanic?

[wunderguy]

I mean something that developers put into a game that you simply loved.

Im a fan of the blind side mechanic from star ocean:the last hope at the moment just because it makes combat much more fun.

 

[Soxafloppin]

Any game that has bullet time is awesome.

 

[Satoz]

I like the abillity to toggle between 1st and 3rd person, I generally prefer 3rd person, and for some reason first person always makes me feel odd when I can look down and see empty space where i should see some chest, arms and legs... when they do have it its more bearable