The way the options are set up it's really easy to block someone you meant to follow..
Devil Inside, for example, I think I blocked inadvertently, now I'm blocked back!
Most Helpful Girl
Nope, not that I'm aware of... it goes both ways, when you block someone or they block you, any possible form of contact between you two disappears.
I doubt people would tell you why they've blocked you even if you asked, anyway... but who knows.
The FAQ gives a description of all that happens when users block each other,