Cat destroying your things.
A Hollywood production you paid $20 for (with popcorn) and you're left with 'what the hell was that.'
Angry Cosmo Kramer, "C'mon, what is this!? Amateur hour!?
Applied to Work:
Boss: "Damn it Johnson! These papers are NOT in alphabetical order. What is this, Amateur Hour?"
Applied to Video Games:
Player A: "Wow, that kid is using a glitch. I forgot it was amateur hour this time of day."
Applied to Home:
Mom: "Rodney, your room is filthy. I thought I said clean it."
Son: "I did clean it."
Mom: "Did you clean it during amateur hour or something? This is atrocious!"
Applied to School:
Professor: "The class average was a D+ on this exam...seriously class, is it amateur hour when you all come here?"