For example, way back in the dim and distant days of the early nineties, I got into Oasis in a big way. Was completely obsessed with their first two albums/ However, their subsequent tendency to just keep repeating the same Beatles rip-offs combined with their utterly obnoxious public personas actually drove me to the point where I no longer even enjoy those first couple of albums, even going so far as to get rid of them. (Although I must admit I quite like The Importance Of Being Idle - I guess because it's a Kinks "homage" for a bit of variety.)
It happened with Heroes. Here was a programme that I was completely addicted to during its first season. It was a lot like a TV version of all the best parts of X-Men comics over the last 25 years. Then came the lacklustre second season (curtailed by a writers strike) and a third season so devoid of anything resembling character development and plot coherence that it resembled all the worst parts of X-Men over the last 40 years that I jumped ship and haven't looked back with regret once.
How can something so filled with promise go so wrong? I guess in each case there are a myriad number of reasons as to why something successful sadly stumbles down the path to failure. I sometimes begin to suspect that some things only have a finite amount of greatness attached in them. Maybe this band only has one great album in them. Maybe that writer only has one great book in them. Or maybe it's a byproduct of the way certain aspects of culture accelerate so that we demand more and we demand it faster and creativity doesn't have a way of keeping pace with demand. Either way, it's always a sad day when something that once gave joy becomes a source of disappointment.