People are pretty simple to understand to be honest.
They want "value". For that, they want length and lots of stuff. They want to feel satisfied.
Colossus gives that because it's quite a long ride and OMG IT HAS TEN LOOPDELOOPZ!!!!
Stealth is a buzz. It's bam, woosh, end. So people love that short buzz, but they feel like it's just not been worth the long wait.
Okay, some people are more discerning, but not many.
Also... The reason only enthusiasts tend to complain is down to the pleasure/pain factor.
If we are a member of the public, we may do one or two parks a year. Maybe ride a dozen times over a handful of coasters. The pleasure you get is more intense because it's something you don't do often. So you tend to forgive the pain, as you're doing something special.
Also... If you don't ride often, there's a chance:
a) You don't really understand it's pain making you dislike the ride. You just come off thinking "I didn't really like that". Enthusiasts often forget the confusion adrenaline causes and how it makes you forget things (and seems to speed time up).
b)You forget you hated it last time because it was more than a year since you last rode it. You don't remember the 20 seconds of ride, but you do remember the exciting build up in the queue and the positive day you had which makes you think you did enjoy the ride.
It's all simple psychology
