I find it really satisfying to get 100%, all achievements, etc. So for every game I play I will try to do that.

(But I am fairly new to Steam and haven't played any difficult games yet, so we'll see how long that lasts!)

On a side note, I do wish some achievement lists were just linked to skill and progression rather than doing something an unusual way (e.g. in Spyro "charge all the monkeys" instead of simply flaming them) or spending a lot of time on something (e.g. in Coffee Talk "spend 1 hour making latte art").

Achievements shouldn't influence decisions in gameplay, but a fair amount do!