I will do my best to get them all if they're fun ones or at least not annoying to do. Otherwise I will not bother. The reason I play games is to be have fun and to be amused, not for pictures of trophies or a useless number.
Getting to rank X (requiring a bazillion XP in multiplayer matches) in a no-bells shooter is a very very bad achievement or trophy and unworthy of my time, for example.
Killing 50 enemies with a rocketlauncher is also a bad achievement and I will not actively pursue it.
I remember Ratchet and Clank's skillpoints, those were fun to do.
Often when doing something unusual you got surprised with "Skillpoint", you look up what you did, think "Oh, yes, I did do that, notice "4 skillpoints, 5 needed for Big Head Mode" and then the hunt is on, baby.
Try to get on top of a large statue, beat a boss with nothing but your wrench, destroy a whole bunch of scenery, etc.
Not too difficult yet sometimes challenging, unlocking small in-game sillies and having a clever description when you view them later on.
Why don't many games have ones like that?