I use a real computer (what's an "unreal" computer anyway?), and I paste using right-click -> "paste" or CTRL-V, or SHIFT-CTRL-V if it's in a terminal. What's wrong with that?
It requires cooperation from the program you paste into.
With X Window System where left-mouse-drag automatically copies and middle-mouse pastes into any program as if you had typed the text, you don't have to worry about whether paste is supported or not, or how it does it (Ever tried to paste from a web page into, say, Outlook, and you get an unwanted table around the paste because what you copied was in a table? Or got a font or text color you didn't want?)
With mark / paste on middle-mouse, you can be fairly certain that you only get the text you marked. And even more importantly to some of us, it works great with partially overlapping windows - just because you paste some text into a window doesn't make that window pop to the front and obscure what you really were interested in, most likely what you copied from.