Ctrl+C when there is no text selected copies an entire line. This always surprises me when it happens, and it happens a lot since I am the type of person who can't manage to hit Ctrl+V to paste reliably.
When the text I have on the clipboard is from a cut command within the same document (usually the case) I have to hit Ctrl+Z a few times to undo the cut, hit Ctrl+X to cut again, and then find the old place and paste correctly this time.
When the text is from another program or tab within sublime text, I have to switch over to it, find a way to get the same selection, and then copy it over to the place I want to paste.
Both of these are time-consuming and break up my workflow. Most other text editors simply ignore Ctrl+C when there is no selection, which is great because I can just correct my keystroke and I am off again. Perhaps this is already implemented as an option, in which case this is simply a +1 vote for making that the default (I would love to know how to do this though, since I can't figure it out). Otherwise, I think Sublime Text should definitely implement this.