That being said, it's an incredibly effective system. There are two different lines - one that stays within the city limits, and the RER, which travels outside of the city to the suburbs. The entrances to the stations vary quite a bit, but most of them have quirky architecture and look like this:
They're all different, though - for example, a few have an older design:
It's not too hard to find the correct line once one is inside - there are maps everywhere, and tables with estimated arrival times.
The RER trains look like this - and the regular trains are pretty much the same thing, but with only one floor.
RER trains are especially cool because they're nearly silent. Most trains squeal as they take off and stop, while the sound of the RER is more like the sound of a giant exhale. I guess that's a cool way to think of the trains - the lines run all over the place, kind of like veins that push trains through with a slightly erratic pulse.
I guess you can tell that I need some sleep.
The most interesting part is the fact that each of the stations are completely different. Some are tiled; some are simply chunks of cement. A few have multicolored, round chairs that remind me of the painfully bright Easter eggs I used to dye as a child; some have dull, silvery benches. Also, depending on the time of day, the people that fill these stations are interesting. On some particularly hellish days, the stations are filled with people who pack themselves into the trains like sardines, compelling me to grip my belongings so firmly that my knuckles turn white. On these occasions, the pea coats and scarves all blend together to create a mass of people that flows in and out of the various tunnels.
At times with lighter traffic, though, it's easier to notice the individual people. The sans-abris, homeless people, washing their few belongings in the rainwater dripping from one of the entrances. The woman that curses when she realizes she's missing an earring; the man with a weathered face that sits next to me. The jolly gypsy playing a trumpet (a video of whom will be uploaded when the internet gets better!); the children, clad with thick-framed glasses and coats that swallow them as they babble unintelligible French syllables.
The metro, when not stressful, is a fascinating place!