Yonks ago - late '90s? - I went to the Tate with a girlfriend. It was her idea. We were looking at YBA shit like Sarah Lucas' "Sod You Gits" and I was taking the piss out of the descriptions while she pouted and told me I was closed-minded. I didn't care, I'm not a big fan of galleries - I find them a bit depressing - and wanted to get the hell out of there because it was a nice sunny day.
Eventually, she agreed I was a philistine, so we were heading for the exit...and ran into Leonor Fini's "Little Hermit Sphinx". It blew me away; I was sucked into it; it was like I'd left the gallery light years behind and the painting was alive. I can't really explain why I'm obsessed with it; I'm sure some will just think it's ugly or murky. My g/f did a complete 180 and started tutting and complaining about 'pretentious crap', but I was barely listening - I was mesmerised and didn't want to leave. Anyway, it's the only painting that's ever had that effect on me.
Apparently Fini once swore at Picasso and slagged off his art, which makes her cool in my book.