I think the trouble with auto is that when it works you think 'Yeah, that's better' and on your merry way you go. Trouble is that you don't stop to think 'Could it look even better if I knew what it was doing and did it myself?', and the answer to that is yes.
It's worth taking the time to work out what each of these autos is doing and then attempting to do it by hand, no slower really and will always give as good but usually better results.
