More precisely, "If I lived in a town where a criminal gang would kill members of my family, confiscate my property, and oppress everyone, and someone came in to kill the gang and stray gunfire killed my family". In the case of a legal invasion (pretty clear in the case of Afghanistan), that someone would be the police; in the case of Iraq, that someone might be a random concerned citizen.. I would definitely be upset, but it would not be murder -- it would be anywhere from purely accidental to some form of manslaughter. During a legal war, it is clearly legal, provided the belligerent obeys the law of war. Depending on the exact situation, I would be more or less upset; there are definitely situations where I would remain very upset (i.e. if the shooting was highly negligent).
Under pashtunwali, accidental death during a conflict, if you take responsibility for it and apologize, is not the same level of offense that it is in western culture.
The quality of life in Afghanistan is probably better today for 90% of Afghans than it was in 2000, although definitely worse than it was in 1954.
In Iraq, the quality of life is absolutely better for the Kurds, and quite possibly better for most Shia, than it was under Saddam. Around 2009 and 2010, it's probably reached the turning point of being better on a daily basis than it was in the past, at least for those who didn't leave Iraq; there are definitely displaced persons who are worse off. I don't think the decrease in quality of life from 2003-2007 was inherent to the invasion, but to incompetence during the occupation -- if the military vs. state department were doing the same thing today, it would have been a lot less bad. Perhaps still not worthwhile, but definitely less bad.