It sounds like you can't imagine different scenario's so that "bothered him" and "angry" seem or feel too much alike?

What I do in that case is put myself in the therapist's shoes; how would I feel if I were a businessman with my own business, Perna, Inc. :-) and I advertised for employees and hired one and six months after we started working together she said, "You know, I interviewed with you because I really liked that you have two cats like I do and you have been married over 20 years. I did extensive research about you, read everything I could about you on the Web".

I would be a little bothered/worried because I wouldn't necessarily remember all there was (and there's a lot) out there about my personal life offhand and I'd really wonder about someone who picked me based on my having two cats like they did, what's that really got to do with our business together? It might have a lot to do with what this person who researched thinks, but I can't know what they are thinking in specific about all these personal things and how they relate to our working together?

It looks to me like you have both too narrow and two wide a focus; you are thinking just about the lookup of his personal information and how that single fact makes you feel but why you chose him and what you thought about the whole thing, based on that lookup is important too (and especially may be to him) as you could have a lot of personal thoughts about him/his stuff that might influence or damage your work together now and he needs to be aware of that. But think of what you "learned" when you researched him versus what details you told him? It's the details and how/what you may feel about them, how you interpret them, that now may be important but you probably did not go into that much detail when you "told him" about researching him?

So, he's "bothered" by the lookup because it adds complexity and his personal information may enter into your thinking now (and you're supposed to be thinking/concentrating on you, not him) but "anger" doesn't really have anything to do with it?

The emotion of anger is needed to help us "do" something about a situation that is harming us, to become aware of it and help figure out how to "solve" it and get it to stop harming us. Your T is not harmed by your knowing his information (it is out there, presumably in the public domain somewhere for anyone/everyone to see), he doesn't need to "do" anything about the situation for himself, his situation has not changed/does not need changing except insofar as he needs to now work a bit harder to make sure that what he says isn't misinterpreted by you because of what you may have found out about him.

For example, you know where he lives. If you know he lives in a "rich" neighborhood, how is that going to impact whatever fee you have to pay him? How is it going to make you feel if he has to raise it in a year's time? If he has no clue (which he doesn't until you tell him) you are thinking about that rich neighborhood when you have a discussion about raising the fee, you might feel negatively toward him for raising his fee and how's he to know where it's coming from? If you don't express the feeling outright, don't bring it up to him but merely get some sort of "attitude" he's helpless to figure out where it's from and, if you're newish to therapy or not good at locating/expressing your feelings yet, you won't be able to tell him! It might not cross your radar what's wrong but could end up being a big deal and both of you may be "helpless" to work it out because he can't know what the problem is and you aren't able to realize it yet.

In a sense, it's dangerous to you because you may quit therapy because he raises his prices and, even if you are able to say, "Hey, you live in a rich neighborhood, how come you're raising prices!" you may not believe his answers because you have already decided it's a "rich" neighborhood (so everyone must be rich who lives there; woe be unto him if he inherited the house/neighborhood from his parents or former spouse :-) or, he might have to go into more personal detail than he'd like with you (expensive medical procedure for spouse/child or supporting own parents, etc.) or several other things we could imagine. He might not see it as a rich neighborhood; but how is one to argue personal definitions of what "rich" is? You now have "opinions" of him, based on basic/no-opinion, literal facts. Not good if one has a problem with a run-away imagination or too-rigid beliefs, etc.