I have recently been doing a bunch of web side projects through word of mouth recommendations only. Although I am much more a of a programmer than a designer by any means, my design skills are not terrible, and do not hate dealing with UI like many programmers. As a result, I find myself lured into a bunch of side projects where aside from a minimal back end for content administration, most of the programming is on front end interfaces (read javascript/css).

By far the biggest frustration I have had is convincing clients that they do not want Flash. Aside the fact that I really do not enjoy Flash "development", there are many practical reasons why Flash is not desirable (lack of compatibility across devices, decreased client accessibility, plug-in requirements, increased development time, etc.). Instead of just flat out telling the clients "I will not build you a flash website", I would much rather use tactics to convince/explain to them that this is not what they actually want, ie: meet their requirements any better than standard html/css/js and distract users from their content.

What kind of first hand experience do others have with this? How do you explain to someone that javascript/css/AJAX is usually a better option for most websites? Why do people want to use Flash so bad to begin with?

This question pertains to clients who do not have any technical reasons for wanting flash, but just want it because they think it makes pretty websites.