Perpetrators: Microsoft, Sony, Valve
Worst Example: Far Cry 3
Remember when simply beating a game was reward enough for playing? Ever since Microsoft introduced the achievement system with the Xbox 360 there's been a dramatic shift in how players are rewarded in games. On one hand you've got the constant bloop-bloop notifications every time you beat a level, kill a miniboss, or collect 50 golden sparrow eggs, but they've started seeping into the actual design of the games now.
There's nothing inherently wrong with giving your player a little pat on the back for accomplishing something truly remarkable, but at it's worst the propagation of this constant player-affirmation is making for less engaging experiences. It's truly rare now when I actually care about an accomplishment in-game because when I've already been applauded for every little move I've made up to that point. Hell, they hand out ribbons for dying more than everyone else in multiplayer now!
The Solution: Keep achievements, but make them only apply to monumental tasks