Painting is my shit dude. I'm probably the biggest art nerd on the board, seen dozens of exhibitions although admittedly I've yet to see anything in Europe. Most impressive piece I've seen in person is probably Napoleon Crossing the Alps by Jacques Louis-David, although it's harder to get the full force of it without it towering over you (I've seen Persistence of Memory at the MoMA but it's really just a tiny thing) https://upload.wikimedia.org/wikipedia/commons/f/fd/David_-_Napoleon_crossing_the_Alps_-_Malmaison2.jpg
Here's some other faves off the top of my head. Also dig anything by Dali, Bekskinski, Ernst, Bacon, Caravaggio, Auerbach, Stella