That has emotional content so its fine by me. I think it is also length that is the key - he reacts to what he is seeing, then presumably moves off and does or says something else.
I think where a lot of problems turn up is in info dump time. It is the length of something. Even if you have emotional content with the observation or thought, if someone rants on in their head for three pages about the brainless bosses, the reckless relatives, the pestilent priests etc, etc, or equally eulogises the wonderful woman, marvellous man yada yada then my eyes glaze over. A paragraph yeah, three pages, no. How long is it before it gets boring? Depends on what you are saying.