The fault lies not in the actual "jobs" but the fact that they're never finished properly. They get started, partly done then ended before ensuring a lot or the resulting mess and aftermath is cleaned up properly.

In Iraq, due to outside "pressure", they couldn't wait to get out of there leaving the way open for loads of arms "dumps" to get looted by opportunistic criminals who then took over large areas mistreating civilians along the way.

The reason no-one wants to wade in with ground troops is that unlike in a "conventional war" where front lines are more or less defined and your enemy is "over there", in the current Middle East you have no idea whether the person (even children) in front of you is an innocent civilian, a soldier or a terrorist suicide bomber. Also, you have no way of knowing where all sorts of booby traps are waiting in the most innocent looking places.