You only dance waltz in some weddins or in very specific (usually middle age clients) clubs.

Flip flops have never been admitted except in beach clubs, but I was told in this board that last year they begun to do it in some clubs even in Madrid.

Anyway, I don't think you'll blend in with them because we tend to dress up mostly.

Put out what you think you want to take, then put half of it back in your wardrobe, as I always take too many clothes. Also, you'll probably end up buying some clothes while you're there. You won't be able to resist!!

I meant flip flops for during the day for walking around. Especially in university towns and in the south. I did not expect to see it at all.

Not at night time for clubbing. At night everyone is a lot dressier.

I personally don't dress like that, not that there is anything wrong with it, but it is just to casual for my taste. Plus as a tourist, I may be in a museum, then a church, then a fancy resturant for lunch... you want to be dressed for whatever comes up!