(I have flown on Southwest. Once. I got to the airport two hours early for a domestic flight. Waited in line for an hour and 45 minutes to check my bag and get a boarding pass. The boarding pass was "the wrong one" and security wouldn't let me through. Ticket agent didn't care. Gate agent didn't care. I then ran around the airport like a crazy person, "oh, you can connect in Kansas City, go to gate whatever". "She told you that we had room? HA! Try Oakland." Then I was stuck in Oakland for 6 hours.
This was before I was a frequent flyer and perhaps I was being stupid. But I have missed a fair share of AA flights and have never had any problems.)