Sorry, just wrong, right there.
Can you get me one reliable source which says he has been offered the Real Madrid job when with us? From what I understand he has made the shortlist, but never been offered it. There are a couple of reasons for that. Firstly, his style of football is not what the Bernabeu crowd like, at all. And secondly (this is important) Florentino Perez does not get on with him.
I also think to say he's had to put up with more rubbish than elsewhere is slightly exaggerated. In southern european football things like this happens all the time. In Spain there are elections for the president, each candidate often outlines who they will appoint, and all this whilst a coach is currently in the job. He also had to work with a sporting director who bought the players for him in Valencia. The conditions in which he operates here give him greater powers than he could ever expect with a Spanish club.
And why did he choose Liverpool? There was an interview on Radio City which made it pretty clear that it was the 5-year contract which sealed it. Rafa wanted stability and job security, more so than money. He's had that by the bucket-load here.