I've flown Ryanair twice and it was deeply unpleasant both times - never again. The first time was many years ago, Dublin-Bristol. It didn't help that it was the first time I'd been on a discount airline and the first time I'd flown alone (without DH) with DD1, who was a year old, so was a lot more nervous than now (hardened to EasyJet and flying alone with the kids). I was screamed at by an insolent stewardess when boarding because I'd dared to ask what to do with the buggy, then when I got on the plane with DD1 in my arms I couldn't find an empty seat - Friday evening flight, full of tired commuters - and got snapped at by another stewardess for not sitting down. Er, where? They made no attempt to help me to find that one elusive seat, just stood there and snarled at me.
Then when we got to Bristol, on a direct flight that I had checked in for in plenty of time, they had lost my suitcase. I was flying in for a wedding the following day, so had to borrow a load of fancy clothes, and we had to buy some stuff for DD1 as well. It was incredibly difficult to find anyone from Ryanair to report the loss to, and then they said it would take until Tuesday (another four days) to get the case to me - but as I flew back to Dublin on Tuesday AM that wouldn't have been much use! In the end I threatened to sue them, go to the press, whatever and it worked - they got the case to me the following day - this was 12 years ago, I imagine that tactic wouldn't work now (ie they officially don't care now).
The second time we flew with them was about 3 years ago, Berlin-Dublin, thought I'd give them a second chance, just in case I'd been really unlucky the first time. I normally don't buy any food on these 'budget' flights, but due to the time of the flight the kids were a bit hungry so I got them a sandwich each. So I gave the stewardess a banknote, and a few pounds change was due. She said 'I don't have change now, I'll get it back to you', and walked off. She didn't come back. In the end I buzzed for her, and at first she tried to pretend she had no idea what I was talking about, then sulkily said OK, I'll get it. She came back with a pound, which was still less than we were owed, but I thought, what the hell, forget it.
I'm not demanding British Airways type full service from these carriers - I fly frequently with EasyJet and accept that I will pay for checked luggage or extra services in exchange for the convenience of having a cheaper flight that goes exactly where I want. But I do object to being treated like a heap of shit when I'm a customer, and I seriously object to being stolen from by staff. People make the analogy of going on the bus for these airlines - you wouldn't expect free food on the bus etc. Well, no, but I also wouldn't expect any bus company staff to treat me as shoddily as Ryanair staff do.