I wanted to create this thread because this hasn't really been done before.
I have traveled, and have been fortunate enough to have positive experiences in most places I've been to. Because of that, I'll post a list of the cities that I like later (so hard to choose). However, there have been a few places where I just didn't like my time there at all and at times couldn't stand it. Here's some from the top of my head:
Phoenix, Arizona - This plan is a sprawling concrete jungle. I really didn't like the seemingly baron scenery of the area. And let's not get started with the heat. I found it hard to acclimate to the dry, baking heat of Phoenix in the summer. I thought Houston was bad, but this takes the cake.
Jacksonville, Florida - You would not even think that this is the largest city in Florida. I was baffled when I was informed that this city had some 800,000 people. There doesn't seem to be a lot going on in Jacksonville. The potential is obviously there, but no one seems to want to utilize them.
Myrtle Beach, South Carolina - I LOATHE this place. Absolutely hate that abominable town. It embodies the "trailer trash" image in every way.
Fresno, California - This is pretty self-explanatory.