Maybe you were in a bad mood today.
Maybe you caught LAX at a bad time.
Maybe Both.

My experience in T6, after nearly 100 departures since they changed back to T6, is that it's great. The staff are excellent, I rarely wait more than 5 min to get helped, even if I need to see an agent, and I have NEVER taken longer than 15 minutes to get through security. Usually less than 10 minutes.

AA's Elite section in their LAX terminal is much nicer, 'appearance-wise.' But the service is seldom good, lines are always longer, and you have to stand in another TSA line with your bag after checking in (that is not just for elites, and sometimes very long). It's much less enjoyable than T6.

LAX, as a whole, is not a great airport. It's old, and not well maintained. But I cannot say negatives about the T6 staff or wait times. They have helped me out many times. ^