I think Pietro finds Wanda's friends a little bemusing, because it seems like Wanda is probably better at having/keeping friends than he is (though he's fine at making them/getting along with people). As long as Bobby doesn't seem to be bad for Wanda...
I suppose Cecilia would also be the one who's had to deal with any consequences of Pietro's recklessness that he couldn't actually pull out of, which I'm sure there have been some. So she might be wishing he would pick up a bit of her powers.