I have been asked before what kind of things deserve a straight red card in soccer by new referees, by new fans and by soccer novices.
Well, some things are obvious--striking a player in the face outside the run of play. Striking the referee is a good way to end your day as well.
Oh, then there is this tackle:
I love this comment by the fellas at Dirty Tackle. The referee initially only showed McManus a yellow card, but then the assistant ref pulled him aside and side something to the effect of “Are you serious? That deserved, like, eight red cards.” And the mistake was then corrected.
Of course, the interesting thing about this play is that if McManus had been a little closer in his timing, i.e. not so blatantly late about it, it probably would have gotten just a yellow and that would be all.
So it is just a matter of degrees.