Unobtrusive is great but what about unencumbered?

So in the last few years javascript libraries and snippets have popped up like spring flowers gasping for light. One will round corners for you, one will make an image pop out at you, one will make a box spring open, one will make a drawer slide, and so on... All of these libraries, it seems, have their struggles and inadequacies much the same way a CSS/XHTML developer does; browser behaving badly. Where it gets infinitely more complicated with the javascript is that some libraries and snippets will inadvertently interact with one another from time to time, and that's where a whole bag of ugly gets thrown upon the table. What makes this worse? The fact that we can now just throw these bits of javascript sweetness in our html projects without the foggiest notion of how it works and how to fix it should the need arise. And since these are all open source projects, don't expect great support, or any at all, for that matter. And so this is the muddy water I currently stand in, waiting to sort out a scripting issue on a product while I tell my client base that we are doing everything we can.