I also had a look at the Courtauld general exhibition, and was particularly taken by two paintings, both of women who seem to me sad.
The first, unoriginally, since everyone in the gallery stopped to look at it, and it is widely used in publicity material, was Manet's A Bar at the Folies-Bergère.
The woman is described as a barmaid, but she seems far too well-dressed, and too vulnerable, to be that. The back view of her, which is almost but not quite a reflection, makes her look like a schoolgirl, with her ears reddened with embarrassment as the sinister-looking man leans towards her.
A really disturbing image.
The other piece that struck me, Vanessa Bell's Conversation, is less obviously confronting, but my reading of it is the woman on the left in black, who is speaking is telling some tale of familiar misery that the other two fashionably dressed women have heard many times before, and while they're putting on a sympathetic front, they're a bit bored with it. The reproduction doesn't really do it justice: go and see it would be my recommendation. (She was the sister of Virginia Woolf, by the way.)