Continuity: The movie is supposed to have been filmed and taken place exclusively in Pasadena, TX, and MOST of it is. The trailer park that they live in, however, is NOT in Pasadena, or anywhere near there. There are several scenes where they show someone driving into the trailer park, and you can see mountains in the background.  There aren't any mountains within hundreds of miles of Pasadena. 

Other: In the scene where Wes is drinking the tequila with the worm in it, he makes a toast to "la vida luna" and tells Sissy it's Spanish for "the crazy life". This is untrue, the correct Spanish translation for "the crazy life" is "la vida loca". "La vida luna" translates to "the life moon"

Continuity: When Bud and Sissy are driving to their new home, the camera shows their names on small license plates in the rear window of the truck. They arrive at the house, and you can see a bunch of people and streamers in the back of the truck. They were not there when the license plates were shown.

Other: When Bud is hit by the mechanical bull, he jumps up shouting "You broke my godd**n arm.", and this is a point thought the next 45 minutes or so. The cast he is seen wearing however is only given for a broken thumb, not a broken arm, which is where he was hit.