I DO like me my trophies. In fact, I'm currently racing with three other friends to see who can be the highest level. I started out in last place. I am now in second, and closing in on the leader. He's at level 16 and is starting to freak out because it's dawned on him that I'm closing the gap faster than he can widen it. I'm now at level 14, 80%, and with the game drought coming to an end this Tuesday, the race is ON!
That said, I will attempt to get 100% on games if I believe I can. Most of the time, these are RPGs or shooters, as they can be done fairly easily (Modern Warfare 2, Alice: Madness Returns, etc). However, sometimes a game will throw a trophy at me that I simply can't get. To this day, I still haven't completed "Mile High Club" and "No Fighting in the War Room" on veteran because of the stupid time limit. I also can't get all the combat challenges in Batman because some of the scores are insane.
Then there are games like InFamous and Mass Effect (not Mass Effect 2), where I could totally get the platinum trophy/all achievements, but I don't want to because some of the trophies are linked to being evil/mean. I just can't do that. My conscience won't let me. It tore me up enough getting the platinum for both Dragon Age games. The only way I could do it was because I told myself the choices weren't evil, they were just matter-of-fact and unpopular.
Finally, there are games with multiplayer trophies. These games need to die. Call of Duty did it right by having no trophies linked to their online. If I decide I'm going to get online trophies, I start on those first, the day the game comes out, because no one knows the game yet so it's easier to get a 7-killstreak reward (cough Medal of Honor cough). After that, I never touch the multiplayer again because I view it as a chore, not something to do as fun.