I thought Stokes dealt the situation at handshakes pretty calmly to be honest! If someone stuck the shoulder in at handshakes in most other sports the result certainly wouldn't have been as gentle.
As for the celebrations, whatever Buttler said to the media it clearly wasn't just the celebrations (ridiculous though they were) that caused his reaction - watch the video, he's walking away and obviously reacts to something that was said. Umpires were right there so surprised the match referee hasn't got involved by now. Good to see that Mashrafe appeared to go over to Buttler and apologise after the game though.
Edit: oh whoops, match ref has got involved now - Reman and Mortaza fined 20% of match fee and Buttler officially reprimanded.