Consequences, and when things go wrong or not as planned

Has anyone suffered consequences by mixing traditional techniques? Has anyone not quite worded a spell right and had it turn on them?Have you or someone you know messed with or mixed magic that should not have? I know there are somethings that might have certain side effects. Since eclectics and chaotes experiment the most, I figured I would post this here. The purpose of this thread is to discuss consequences and negative reactions to magic not done properly or just wierd consequences to well put together spells.

Any stories, experiences and musings related to the topic are appreciated. Thanks!