For those of us who remember a time before home versions of microwaves and computers and before DVRs even existed (my mother grew up in western Canada in a house with no electricity or plumbing, and she rode in a small horse-drawn wagon with her sister to school everyday) it can seem incredible that we begrudge ourselves even a few extra key clicks, but such is the situation we find ourselves in.
One click on reply w/quote can save a few key clicks, but unless edited down it's way overkill in most cases, it's difficult to fix when misedited, and abuse seems impossible to prevent. I suspect it might be going away soon, so I offer this "Did you know..."
Did you know that you can select text in your browser window and drag and drop it into a message box? Well you can! Try it, you'll like it!
It's even better than that - you can drag and drop selected text, even links, from any window directly to your message box.
One frequently requested feature is the ability to click on buttons to add codes to your message box. There would be buttons for bold, italic, quotes, etc. Clicking on them would add the open/close codes at the cursor location, and if text were already selected in the message box then it would be embraced in those codes. This is on my list of things to do, but as I keep saying, I'm just one guy.