1! You step outside your door and there is a feast. Drumrolls, holy processions, horse racings traditions kept up since hundreds of years and food food food. Sweden, for example, can not compete with that.
2! Chatting up people on the street is so easy (more easy on the countryside obviously but still) and you hang out with friends till you REALLY have to go home because it is the next day and work starts in an hour so you better change from the party clothes.
3! It's cheap! Not in Madrid and touristy places, but here is a benchmark: 10€ offer for a lunch menu of three dishes
4! It's full of history! Ruins ruins castle church ruin cave paintings UNESCO was here El Greco intact Roman constructions etc.
5! In the south, the stable sun.
6! It is the country of salsa and bachata and I have not gone yet but I totally will!
What about you, are you convinced?