Players square up to each other all the time, we can't go booking people just for squaring up to another player. Yes, Aguero has gone down very easily, but Fellaini has still headbutted him. We shouldn't defend Fellaini here, the guy is a moron and the sooner Mourinho gets rid of him the better, I absolutely hate him.
On a different subject, for all those who constantly bash Mourinho and United there's an interesting article on Fivethirtyeight on how United are unlucky not to be higher in the league and statistically are a lot better than people give them credit for:
https://fivethirtyeight.com/features/manchester-united-is-too-unlucky-to-be-great/
Also, if United avoid defeat to Swansea it will be a new club record undefeated run. Say all you want about the football we play, but that is still very impressive. I think we're absolutely on the right track with Mourinho and with the right transfers I think we'll challenge for the title next year.