Have you ever copied a very long URL spanning multiple lines and then tried pasting it in the address bar, just to find that only the first part of the URL was pasted? Yeah, having to remove the line-breaks manually is a pain. The good news is that Firefox users could easily fix this problem. Just go to about:config and look for the following entry:
Just change the value to 3 and voilà! No more multi-lin URL hassles.
I forgot where I got this tip from, but thanks dude, whoever you are.