(A collection of some thoughts brought on by recent posts and posters. Some of these are touched upon in the FAQ and Pseudoscience section, and these sentiments can be found on other science fora)
If you think you've toppled relativity, quantum mechanics, evolution or some other theory with your post, think again. Theories that have been around for a while have lots of evidence to back them up. It is far more likely that you have missed something.
Here are some things to consider: