Mexican/Tex-Mex ingredients (tortillas, frijoles, masa harina, salas etc.) are so much easier to get in Udon now compared to just a few years ago. But yeah, try as I may, I still can't capture the true essence of Tex-Mex/Mexican that we have back home and quite honestly, I've tried quite a few "Mexican" restaurants in Thailand that simply didn't measure up. The influx of immigrants from south of the border has provided the States with many outstanding eating establishments that definitely know how to turn out the "real deal".
My wife has the same opinion regarding Thai food that is to be found in American 'Thai' restaurants. When visiting the States she much prefers to shop at seasonal Farmer's markets as well as Asian markets and then bring the ingredients home to make her own Thai meals. After living in Thailand for the past 15 years even I can tell the difference when eating Thai food in the States. The missus, by the way, used to hate Mexican food but after eating it in the States she has become a fan. She even suggests it sometimes when deciding where to have lunch or dinner.