Southwest gets lots of positive reviews, but I really don't understand why. If you're not checking luggage, they cost roughly the same as any other airline, and the experience was definitely worse.
The only reasonable connection Southwest offered between San Francisco and Minneapolis had me first stop in Burbank (remaining on the plane) and the changing planes in Phoenix. So I flew three segments on this trip, and none of them was enjoyable. The experience at the airports was even worse than on the planes.
I absolutely despise Southwest's bizarre boarding procedure. I paid extra for "early bird check-in", which gave me a boarding number on their "A" list. Even so, I had to wait a LONG time amid chaotic crowds at the airport and then race like the running of the bulls to board the plane. Even with that, on one of my flights I still had to stow my bag in another row. That's because even though I chose a row that was empty when I boarded, the overhead bins in that row were already filled.
Both of the planes I flew on were old and filthy. I know from the layover in Burbank that Southwest doesn't clean the planes at all when they stop. They didn't even spray or wipe down surfaces. All the flight attendants did was check to make sure the safety cards were still in the seat pockets. This is probably because Southwest tries to turn their planes in a shorter time than other airlines do. When it's 45 minutes or less between touchdown and take-off, there's not much cleaning that can be done.
On all three legs the only service was a tiny package of snack mix and a tiny cup of a non-alcoholic beverage. The flight attendants came across as rude and indifferent, as if they were doing us a big favor to be handing out that tiny treat. They said there was wi-fi available, but it didn't seem to work on any of the flights.
There were lots of children on all my flights, and many of them misbehaved badly. (One little girl spent the entire flight kicking my seat.) Neither their parents nor the flight attendants corrected them in any way.
When I landed in Phoenix I found that my onward flight to Minneapolis had been delayed. No Southwest employee ever gave a reason for this delay, and they acted annoyed that I had even inquired. We ended up 3 1/2 hours late, which got us into MSP around 3am. There were absolutely no apologies given--not by the gate staff, not by the pilots, and not by the flight attendants. Honestly, they were some of the least pleasant airline employees I've ever dealt with--definitely not who you want when there's a delay.
I e-mailed Southwest after this experience. Their response still had no apology whatsoever and no explanation for the delay. They did, however "as a gesture of good faith" give me a small credit for future travel. I'll likely never use it, because I really can't imagine flying Southwest again.