I'm glad he walked out of that interview.
http://www.ew.com/article/2015/04/22/robert-downey-jr-awkward-channel-4-interview
The first few minutes were fine, but I think this interviewer went completely and inappropriately off topic about half way through. RDJ was clearly getting frustrated, but he actually played it really cool. He's talked enough about his past, and if the interview was meant to be about that, then he would've talked about it. This interview was simply meant to promote Avengers, so I think Robert did the right thing.
"Game over, man! Game over!"