The most pretentious thing I have ever SEEN anyone do, rather than overheard, was at our local state primary school quiz night.
School was a real mixed bag of families - some very middle class (affluent area) but also quite a lot of single parents and families who struggle financially due to proximity with social housing. Not judging - just fact.
Anyway. On our table is a real mixed bag, including one of the wealthiest families at the school - massive house, amazing cars - the lot. Mum is LOVELY, Dad who is the high earner with the big job, has a bit of a reputation as a knob but whatever....
We win the quiz and headmistress and PTA mum bring the prize to our table - two huge boxes of chocolates, some bath stuff and two bottles of red and two bottles of white wine. They sort of laughingly joke about how we will divide it up and hand the stuff out. Knob dad is passed the box with the wine in it. He takes the bottles out and reads the labels and then, without a thought for anyone else, HANDS THEM BACK TO THE HEAD and laughingly says "I'm sure someone will eat the chocolates but I wouldn't cook with these. Were they tombola rejects? I"m afraid I can't make room in the cellar for this stuff"
It was awful and embarrassing and our lovely head went bright red as she took them back. About fifteen minutes later one of the mums whispered to me that she would have LOVED to get a free bottle of wine, so I went with her to the head to apologise and tell her we'd love the wine. It wasn't even a nasty desert wine or horrible Lambrusco - it was perfectly adequate pinot grigo and a rioja.
We made a big deal about putting them back on the table and Knob-Dad wasn't even embarrassed but instead, spent an hour droning on about his wine cellar and how wine was made and why the wine we were taking home was shit.
Pretentious cock.