Now you're just being stupid. TXT makes far more sense as a shortened version of TEXT than TEX does..... And as for LOL and the like, those are acronyms - LOL, ROFL, STFU, etc are forum slang, or acronyms, and on the whole are perfectly acceptable.

For example, most see it as fully acceptable to say;

"I went to Donny today and had a great time. Was a proper laugh, especially when I saw my mate fall off the track LOL!"

As opposed to;

"i wen 2 donny 2day n had a gr8 time. Proper laugh specially wen i saw my m8 fall off da trck LOL!"

Which of the above sentences a) makes more sense, b) is easier to read and c) makes you look like a child?