People who use Linux know that copy/paste is as easy as selecting some text and then clicking the middle mouse button to put that text exactly where you want it. No need to navigate your poor and addled with carpel-tunnel left hand all the way over to the Ctrl-C/Ctrl-V combination, saving precious calories.
I used to use this trick in Firefox also. If you highlighted a URL, you could just hover in the window and middle click in there, and it would take you to the page. This was nice, because if you tried to copy it into the address bar, it would keep the original address in there, and then you would have to backspace it out, blah blah.
For some reason, the newer versions of Firefox seem to have this disabled (I think, unless I disabled it in some stupid way, which is completely possible). To enable it, navigate to about:config. This will take you to the secret preferences of Firefox. There, you can set the middlemouse.contentLoadURL to ‘true’, and get that setting back.
Another one that I like is using Ctrl-Backspace to delete parts of a URL in the address bar. It works great on my windows side, but in Linux, it just deletes the entire bar. To get that setting back, I had to set layout.word_select.stop_at_punctuation to ‘true’.
The about:config has all kinds of settings in there that can help you if you poke around in there.