Luke,
Your experience and mine are complete opposites.
I've flown with many instructors for test rides, but really only had lessons from seven.
Of the seven, one (the first one) was an hour builder.
Once I figured out he was there to build hours and not instruct me, I switched to a chap who loved teaching.
From that day on, I always interview an instructor before I take lessons (whether that's IR, CPL, Multi, renewals, or whatever).
During the interview I establish that 1) they're interested in teaching, not hour building, and 2) that they're the kind of person that I can get along with well in a cramped space.
So, six of the seven have been excellent instructors, who teach flying because they love to teach flying.