Shit is different for all dogs. I met my friend with her dog yesterday, her pup is 4 months and travels like an angel and has no seperation anxiety. My pup foams at the mouth within 10 seconds and yelps like a bat out of hell when I leave the room. I had pre-conceptions her pup was already a more well behaved dog than mine despite being younger, and then after travelling an hour in traffic to meet me I thought my worse fears were confirmed. WRONG. Her pup struggles hugely with other dogs and humans, cry's, runs away, and can't deal with other dogs. My friends couldn't believe how social my boy was with both humans and dogs, but more importantly the understanding he had for other dogs and his capability for helping other dogs be social big or small. I've never been prouder in my life.