Heh, when I was younger I was kind of the same way with some of the games with collectibles. Playing the game long after it had moved from fun to frustrating, because for some reason I HAD to beat the game completely. (Part of this was not having much money for games as a kid, so I made sure to wring every last bit of fun out of the ones I had).
I suppose it's allowed me to learn a good lesson and avoid worsening come of my own obsessive/compulsive behaviors, at a certain point when I realized I wasn't actually having fun, I just stop playing the stupid game. 80% complete, 100% complete, none of it matters if you're not having fun, and letting yourself get into that frame of mind can be very destructive (I know people who bankrupt themselves trying to have "complete" sets of sunglasses, all the DLC for various games, things like that).
When I was younger I also had a lot more tolerance for the non-action parts of games, like talking to people in towns in RPGs and stuff like that. I just wanted to consume every bit of content. Now I just want to get into the action. I try playing older RPGs and I just can't be bothered to talk to people and look around for quests, I can barely be bothered to optimize my equipment (unless it's actually fun to do for some reason).
Now most people as they get older say they have less time for gaming, thus their patience with time wasting stuff is also less. While I certainly don't have quite as much time to play games as I did when I was a kid, I still spend a good portion of my time playing them (4-5 hours a day during the week, almost all day on the weekends). So I certainly have time to talk to the townsfolk AND get some action in, I just don't want to anymore.
But once in a while something comes around that pulls me in. Alpha Protocol did, I wanted to talk to everyone I could, I got invested in the story line. Maybe part of the issue is people who write stories and dialog for games aren't typically aiming too high.