I'm going to go
When you say 'I'm going to go' it really means you're about to leave and never come back. It's like you're giving them the boot while still standing in the doorway.
'I'm going to go.', said after you caught your best friend cheating on a math test.
'I'm going to go.', said right before you left the party because the DJ played a Justin Bieber remix.
'I'm going to go.', said after your cousin yelled at you for eating the last of the pizza.