I recently encountered a printing issue in Firefox that eventually turned out to be a problem with the fieldset tag we wrapped the entire page in. (Bugzilla: Bug 471015) All browsers have their own rendering quirks and issues, but it can be very hard to know what's causing different behaviors. Sure, you can Google, but that's often taking a shot in the dark about what you think is causing the problem. It also doesn't stop you from having to sort through multiple complains about the same behavior before you find someone who has the issue your looking for. Are there any websites out there that let you search for rendering behavior issues by browser version, browser function, css tag, or html tag?
I've seen this SO Question, Wanted: Resource for documented Cross-Browser differences, but I'd like to find something more detailed that includes browser bugs.