I'm so tempted to start and end this comment with 'tehe... Cas' but I know I shouldn't.
Basically, this was wonderful. It was canon, it was sweet and I love the kind of childlike Cas that people don't write often enough.
All the reasons this was amusing and perfect:
Cas researching. Cas at the library. Cas watching Dr. Sexy MD. Cas ignoring personal space. Cas making everything uncomfortable. Cas making everything better.
And there we go. Also, this was my favourite line in the world:
But Castiel can also see the small smile reserved for well-it's-Cas situations appearing on Dean's lips, and he smiles as well.
So funny, so true.
The only thing I can find that needs fixing in this is just a few spelling errors, the occasional extra word that isn't needed. It can be easily remedied with just a quick edit.
I love Cas's obliviousness- in Canon and in the fanfiction world, and this was absolutely perfect. I can just visualize Cas saying “Fixing you, of course,” with his slightly tilted head and a confused frown on his face.
Only Cas...
The guy is so hilarious, and he doesn't know it.