Tracy needed somewhere to stay, how was he supposed to know that it was in another universe? Now he'll somehow have to hold down a job on Earth while living as a pony in Equestria. It's either that, or say goodbye to being human.
Song and magic are two parts of the same whole in Equestria. When Rose saw Anon, it was love at first sight, and as if to shake any doubt, she heard their song. It was the happiest moment of her life. Until she realized he couldn't hear it.
A random guy is snatched up and transported to Equestria, where he promptly panics and punches Celestia in the face. She does not take it well. At all.
Humans aren't nearly as robust as ponies. Simple gestures such as hugs, pats on the back, and hoof bumps are all well and fine when it's another pony on the receiving end. With a person a fraction of their mass, ponies forget how fragile others are
With Fluttershy's father about to visit, everypony is more than excited to meet him. Thing is... he's a bit different than what they expected. In that he's big.