Being from a pretty rural town, we don't have a lot of public transportation. Even at school in Raleigh, where there is a bus system, the efficiency is not all that great. Needless to say, I was amazed by the bus system in Spain. The buses were efficient, meaning they were on time, and there were plenty of them. Even if the bus wasn't on time, the system has developed an app, and a website, where you can track where you bus is, and how long until it gets to you.
I'm mainly talking about the buses, because that's what I used the most. When we arrived, all of the students were given a bus card with 20 bus passes on it. Each ride costs one pass, and the card is refillable as you run out. You can even personalize them.
Other than buses there's the metro, plenty of bike lanes for personal bikes, and a system called "Valenbisi" which is essentially a bike rental system. With the Valenbisi you can rent a bike for 30 minutes from a checkout point. Then when you are done with it (or if you need more time, you can switch it out) just return it to a station near you.
The streets are well taken care of, with trees and recreational areas found all over the city. All in all, I loved being in such a big city as Valencia, being able to easily navigate probably played a large part in that.