What could cause this squirrel to do this?

I have a squirrel in my yard the other day, and my dog was barking at it. I thought it was hurt and didn't want the dog to eat it. So I scooped it up with a shovel and put it on my fenced in deck. I set him down and he ran off. Now (3 days later) another (probably the same one) squirrel was in a stand off with my dog again. It let me poke it with a stick and a tried several times to scare it off and eventually it scurried up a tree. What is wrong with this thing. It wasn't acting aggressively but should have been scared of me and it wasn't. At all.