We too have had good and bad experiences at Disney vacations, and also when we have vacationed other places. Working in the hospitality industry, I can tell you that even with the best laid plans, training, and equipment that a meltdown of epic proportions is only a moment away at any time. When it's busy........the chances of multiple meltdowns increases dramatically.
Not that you should worry about that. As a consumer, you should get the experience, product, and attitude that you paid for. When you don't get it, it can be extrememly frustrating.
You can lower the likelihood of problems by visiting at a lower attendance time of year, watching park schedules like a hawk, and planning planning planning, but even with all of that a bad experience is only Cast Member away. I wish that Disney was exempt from these problems, but unfortunately they employ people just like everyone else.
What to do? Complain with a smile, and firmly but fairly demand a fix whenever possible.
I have never had Disney miss-handle a complaint. They have certainly been responsive whenever I have brought something to their attention. When I have sent food back I have received a replacement meal. When I have had a dirty room they have cleaned it immediately and appologized. I have always treated every Cast Member with respect, tipped hansomely, and thanked people for helping. And they have always bent over backwards to make it right.
And my Amazing experiences have always outweighed my poor ones.
Poor Bus Service (probably due to sick calls).....? Travel during less busy times because we all know the system can be overwhelmed. If you go during busy times at the parks, you will get on fewer attractions, so get there at open and hit the ones you like. Know the park hours well in advance and plan. Go the Christmas Party on an "off" day so that the experience is more magical. I think that you have to do a ton of work to have a great time at Disney during any busy season, but in the end the results always have justified the means.
Last Christmas Season I was at Disney with my family. We planned our days (using the Unofficial Guide Calendar, and some common sense that comes from experience). We got to the parks early, planned off days in between, used fast pass extensively, and had a wonderful experience. In the evenings we sat in the hot tub listening to people who had a terrible experience and experienced very few attractions. It was always difficult to believe that they had gone to the same parks that we had.
We did experience some miss-fires and some poor service experiences, but whenever I spoke to a manager or cast member, Disney always responded. Would I go again during the Christmas Season? Sure. Would I do it every year? No way, because it's a lot of work and planning and time. It's really exausting to experience Disney during the holidays. Satisfying yes, but lots of work.
One time we were at the studios to close on the 4th of July. Jillions of people left the park after Fantasmic. They had one tram running, and there was a cast member sleeping in a seperate tram on the parking lot. It would have taken an hour to wait for the single tram. Did Disney plan on having one tram working at close on one of the busiest nights of the year? I doubt it. Were we tired and irritated? Sure. Did it ruin our vacation? No way.
But we won't go back on the 4th again without parking really close to the park!
So vote with your dollars and stay away. I think though that Disney would like to hear about your experience.
Enough rambling. Thanks to the OP for posting.