The plumber unblocking the pipe under your sink is steadfastly refusing to show any interest in what you do for a living, despite the ridiculous amount of questions you are asking him about his own work, it has been confirmed.
You have spent nearly all of the two hours he has spent in your house hovering awkwardly behind him, firing questions at him as if you were Adam Boulton interrogating an evasive politician, yet he hasn't once done the decent thing and asked you about your role as a psychology tutor in your local secondary school.
This, despite your sadly obvious attempt to drawing him in when you passed him a cup of tea by saying 'Hope you don't mind if I go and take a couple of calls - I was lucky school were able to give me the morning away to come and let you in to be honest, what with how busy it is....'.
Starting off with standard chit chat about whether he was busy for this time of year, and how had he been affected by the pandemic, you moved on to increasingly odd queries about how much time off he managed for his lunch, and whether his wife was always asking him to do plumbing jobs at home, all done with the underlying motive of getting him to reciprocate with some questions about your own work, and in turn, making you feel like you have some shared experience and mutual understanding of the trials and tribulations of modern capitalist society.
You now are left with two choices: either refuse to pay or let him leave until he asks you at least one question about whether you live in constant fear when teaching a group of bottom set year 11 kids (you do); or accept that he just doesn't respect you and the gaps between his manual labouring activity and your more cerebral work endeavours are just too great to bridge.
'Nice guy, but classic middle-class inferiority complex combined with the need to validate his own professional identity through engagement and reinforcement activities with others', noted the plumber to his mate as he left your gaff. 'Would have been good to ask him more about this if he'd given me half a chance - I did study it for 4 years in my Harvard PhD after all'.