Most subway stations make you feel depressed and oppressed. They are dirty, crowded, filled with fetid air and not particularly attractive. A few raise your spirits.
I've always liked the 33rd Street Station on the 6 line, and am always surprised by its perhaps unintentional grandiosity whenever I climb down into it. It's a very low-sitting station and you have to descend a great flight of stairs to get to it. Nothing unusual there. Many subway stations lie far below the sidewalk. The difference here is that at 33rd Street you don't end up in a low-ceilinged, claustrophobic box, but in a spacious airy chamber with a great sense of flow and line.
The station was built in 1904 as part of the IRT, and is one of the oldest stations in the subway system. It has a lot of decorative and unusual ironwork, including a long, curving, cast-iron fence that separates the "lobby" from the platform, and some handsome pressed tin on the ceiling. That there's an iron fence instead of just a cement wall lends to the relative openness of the space.
Unnecessarily handsome-looking lamps suspended by poles at least six-feet long hang over the platform. The mosaics of an eagle holding the number 33 are original and date from the opening of the station. They were created by the firm of Heins & LaFarge/John H. Parry Company. The whole station was recently renovated.