David Hayden has a post (ASP.NET AJAX Web Controls - AJAX Experience Without Learning AJAX) that really bothers me. He talks about the different components that he tested for Ajax support, and conclude with:
Frankly, I would like to know as much about Ajax as I could get away with. The problem is that you can't escape from the complexity. You can wrap it, hide it, stash it in the attic and throw away the key, but it will come back and hunt you.
Complexity, meet Ajax, you are going to be best friends.
The law of leaky abstractions holds quite well for Ajax. Eventually, you will need to do something slightly beyond what is supported by the controls, or you will get an error that can't be fixed by setting a property somewhere, or you'll need to debug an issue. Those are the cases where the willful ignorance will come to haunt you.