The problem with Flash is like any technology. When it was new it brought the kind of interactivity to websites that was just not possible before. So everyone jumped on board and created complete websites using it without realising they didn't actually need it. It happens when anything new comes along, or when someone uses something for the first time.

Look at Facebook for example. What is the first thing people do when they create their own page on there? They start looking through all of the available applications and installing loads, then sending annoying invitations to everyone else they know on there. A few weeks later they then start to get annoyed with all the junk they have in their profiles and start to remove it all again.

It is the novelty factor.

With most things you try out every function first before you then start to use it, and probably then won't use half of the features you messed around with to begin with.

Completely flash based sites are become much rarer these days. In the beginning nearly every other site you visited in the late 90's had some elements of flash within it. These days technology has moved on any true programming has replaced flash for a lot of uses. javascript and ajax technology especially. They offer seamless partial page updating and retreival without the need for page refreshes and simple user interaction.

Flash was initially in your face brash design, American style, whereas now we are finally at the point of smart clean design with interactivity being more seamless and it happening without the user really realising.