It's so simple and easy to use, you don't really need any professional orienteering skills to be able to get from place to place, just follow the colourful lines.
I hate the Metro in Paris.
It's so crowded during the rush hours that it's not even humane. Luckily I use the bus when I go to work, but today I had to take the metro home cos I needed to run some errands after work and it was easier to get back home with the metro. Or easier and easier... So it happened to be between 5 and 6 o'clock --> extremely packed. You can already see people standing cheek-to-window style before getting in, but still you have to just find a way to push in. After a while you get used to leaning to some random people and it's actually quite convenient cos if you lose your balance you won't fall as there's no floor space to fall on. Getting out today was a small challenge though. I was able to push my way through and was already standing on the platform but I couldn't get my hand out. I was holding on to my roundshaped rather big handbag that was stuck in between all the people. So there I was trying to pull my bag at the same time thinking which one should I sacrifice - my beautiful handbag or the health of my wrist, that was soon gonna get crushed as the doors would close in a second or two. Luckily some smart man realised to lift the bag upwards so that I was able to get it over people's shoulders. And no sacrifises needed this time.
I could list the pros and cons of the metro just to find out if my feelings toward this public transport is love-and-hate or just pure love. But there is one plus which makes this crowded transportation method a winner. When people are standing so close to each other, there is no way that anybody could be able to lift an axe and hit someone with it. As we all (Finnish) know what happened in the not so crowded underground train once in year 2004...