Spent all day yesterday having inexplicable problems with a web application that I need to use for work. I couldn't figure it out, support guy couldn't figure it out, but it was clear that the problem was something with my browser.
In the middle of the night last night, I woke up, wrote "Check proxy server settings" on the notepad next to my bed, and went back to sleep.
Came in this morning, tweaked my proxy server settings, and now the application works. Yes, folks, I solve problems in my sleep.