Texas, like some 40 states, is an at-will state. That means an employer can fire an employee for any reason, so long as the reason is not discriminatory or in violation of the very few protected activities. Yet, some employees still think they can disrespect their employer. See the story about Charlie Sheen. He has referred to one of his employers as "whatshischeese" and "whatshiscock" in published reports. He described the wife of his executive producer as unattractive. These are things no employee should say in public.
Mr. Sheen has referred to his employment agreement several times. So, I presume he is one of the lucky few who have a contractual agreement that he can only be fired for good cause or fair cause. But, under any standard I am familiar with, disrespecting your employer is good cause. Any local Texas jury would surely agree.
I have screened many employment calls over the years. One I recall referred to some incident in which he was accused of cursing his employer. The caller assured me he did not cuss his employer twice – only once. He seemed to understand quickly when I explained that cussing your employer even once is cause for termination. Under at-will employment, any reason is adequate. But, in cussing even once, that caller lost his right to unemployment benefits. Unemployment benefits are based on good cause. An employee in general will receive unemployment benefits if the employee loses his/her job through no fault of his/hers. With or without unemployment benefits, an employer can fire an employee for disrespect.
So, sure, an employer can fire you for cussing him just one time. And, I think, even the famous can be fired for referring to the employer in public as "whatshischeese."