Just get over it. You got signed off, that's the important thing. You'll see many examples of people who might be awesome pilots themselves but they can't teach others what they know. You'll also see some examples of people who are instructing not because that's what they genuinely want to do or because they need the hours, but simply because they have the wrong personality type which consistently prevents them from passing the assessment for any decent operator. And the latter can be frustrating AF - and this frustration is often vented upon the students. There was nothing personal against you in the fact that some random bloke was obviously in the wrong place. So, forget about that one flight and enjoy all the coming ones (and I'm sure that you will, the good old C172 is awesome for sightseeing trips).