I absolutely LOVE Mexican food (as well as Tex-Mex other variations of mexican food)!!! Luckily, I live in Houston where there is plenty. My favorite dish is carnitas. You can't get them everywhere (and, no, the stuff they have at Chipotle Burritos is not carnitas!) unfortunately. The best carnitas I have had in Houston was at Hugos. The worst carnitas I have had was at Ninfa's (on Kirby, not the original); they were dry and tastless! If you know a place in the US that has good carnitas, please let me know (I travel a lot).
Most of my life I have lived in Southern California and Texas. However, I had to live two years in Boston stuggling to get decent mexican food (ok, there were a couple of pretty good places).