First, let me say that they have done nothing to deserve such an opinion from me. When it comes down to it, I think I'm just an airline snob.
I definitely agree about the leg room and nice seats. I really, REALLY hate the cattle call boarding (enough to make me despise the airline even if that were the only reason!). I understand that has changed, so I'm looking forward to seeing if that makes me feel a little better about it. I still think you should have your seat printed on your boarding pass before getting to the airport, without having to worry about how early you get to the gate -- even if the new number system helps out a bit.
I really dislike the "humor" (?) of the airline, flight attendants, etc. I'm not sure... Unless it's on a TV commercial, I just sort of find it obnoxious. Definitely just a personal preference, because I know a lot of people particularly enjoy that about SWA.
I miss the perks of the other airlines we like to fly such as XM radio, better snack service, etc. Stupid stuff, but it annoys me when I'm flying with them and they don't have any frills whatsoever.
I don't like any of the schedules offered from any city near me. Most of their flights I find have stops, or leave/arrive at very peculiar times of day for a vacation. I don't like that they aren't offered out of many, many large airports.
In general, I love to fly -- but I like to feel like it's not a big hassle to do so. If I have my way, the flight is PART of the vacation, not just a way to get somewhere.
Of course, this is the biggest truth that I have to admit -- I completely understand why it's not as ... cushy? comfortable? pampering? (I have no idea what word I'm trying to describe). It's because I can sometimes fly to WDW for $90 round trip, which is ridiculous in this economy. I'd fly in the Wright Brothers plane if it got me to Disney World for that cheap!