Avengers: Infinity War

the infinity war ending had me in shock and disbelief i couldn't believe it. i was confused on what happened to all of the avengers that disappeared until i looked up the cause of it. I was pissed off the hulk was being a B%&#% on not showing himself. i never understood that. some people said the hulk was scared to fight thanos after what happened when they first fought in the beginning. Why didn't the hulk reveal himself though?