Actually, Ren's not very happy with Xi Feng as it is. Since he made himself a target in the first place in order to carry off the breaking up Shaozu and Kaguya plan. Which Xi Feng qualified by saying he didn't care if Sahozu or Kaguya's feelings got hurt or mental states were undermined.

Then he comes home to find that Xi Feng systemataically worked against everything he tried to do with Shaozu.

So basically, he thinks the whole thing was a setup by Xi Feng in the first place. And he is PISSED.