Most absurd thing with dentists: They do this thing where they check the depth of the little pockets in the gums. It seems to have 0 medical value. Just to be like: "Watch out, it's 2.5 mm now! Two years ago, it was at 2.3 mm. Just so you know what's up."
Ironically, it takes a long time for the whole mouth and is very painful, worse than fixing actual problems, e. g. by drilling.
Mostly for that, I left my reputable high-tech dentist of two decades for a small practice with old equipment that specialises in anxiety.