Hitchhiker's Guide to Spain
Just don't do it. Really. You're only gonna end up shouting at seemingly deaf drivers and cursing every single Spanish person as probably all of them will have passed you by once you've made it through the country. Which is probably only gonna happen with lots of patience or with the help of public transport and foreign drivers.
And don't start complaining unless you know their language for they know only Spanish. Anyway, debates will soon have to touch the question for the general mindset and most likely they will do the rest of the excluding job by that.
Let it be. Skip it, press fast foward, and enjoy the neighbouring countries which by comparison look even more amazing. After a number of days of Spanish deprivation, hitchhiking in Portugal or France will turn you on again: people who talk to you, drivers who stop to take you to a good spot or who stop at all.