Vim 004: Pasting into Vim

If a piece of text is copied into the clipboard and then pasted into Vim (while in insertion mode), most likely the text will be very ill formatted and kind of "drifting" to the right with increasing line number. Especially this is likely to happen when copying from a formatted document but is very unwanted e.g. when code should be pasted into Vim.
In Vim, use

:set paste

to enable pasting from the clipboard.