Considering chimpanzees are essentially our closest living relative, you could probably understand why Chacha the chimp was so pissed off.
For starters, Chacha is a dude. You name a dude 'Chacha', and you're just asking for resistance. Secondly, he's spent all of his life living in a zoo. If chimps are anything like humans, staying in the same place your whole life can get pretty boring. Especially when there's a world of excitement out there just waiting for you to explore it.