first off, for someone who appears to consider themselves more intelligent then anyone else on this board (or the world for that matter), why can't you change your own oil??? then you could use only "correct/decent" tools on your vehicle and put your drain plug back on without using an impact wrench. or maybe that would interfere with your need to continually validate yourself on a message board? secondly, does your car know the quality of tools that are being used on it? last I checked it didnt take that many tools to change some oil

? It sounds to me like you went to a poorly run jiffy lube/car-x and now asume that all chain quick lube joints are filled with careless morons that return your car to you worse off then when you brought it in. do you also think that all middle easterners are terrorists, or that every hispanic in america is here illegally?
I'm no brain surgeon, but I imagine that it's pretty tough to change the oil in you cars when you are in Afghanistan.
The fact of the matter is that finding competent oil changers is not as easy as it appears. I ALWAYS check everything when I have one done because I've experience and witnessed about every bad thing that can happen. For myself, the most common occurance is that they forget to reinsert the dipstick or put on the fill cap. At a franchised dealership where I used to work, I saw cars where they forgot to tighten drain plugs, put the oil back in, and even a guy with a cabinet full of filters because he forgot to change them. I will have to say I never saw a drain plug installed with an impact.
The problem lies in that oil changes are loss leaders for most places, thus they have the entry level $8.00/hr guy doing the work, rather than the techs with all the experience. This isn't to say there aren't competent oil changers, but that there are many who are not, and that there is a ton of turnover at the position.
I refuse to change my own oil because in reality I can't afford to. For the time it takes to screw with it, I can make a lot more money. I trust others to do so - but always verify their work.
I really don't know why you went off on him. Did his comments strike a little too close to home?