"What do they feel like? Usually." He's curious and the slight sympathetic tinge to his tone is probably because he's aware of how difficult it is to put that kind of feeling into words -- if someone asked him to describe what an aura looks like, for example, his answer would be a lot of weird similes verging on nonsense -- but he's curious nonetheless. If it's not something he can do now (he suspects it's something he needs to re-learn how to do), then maybe he can figure it out later.

Knowing what people are before talking to them is useful for many reasons. He's thinking of some of the nicer (read: more naive) ones.