Possible Clues:

• "I've ___!" ("Enough is enough!")
• "I've —!" ("Enough!")
• Finished receiving commercial success
• Dealt with enough frustrations
• "I've __ up to here!"
• Taken as much as one is willing to
• Finally lost one's temper
• Reached the end of one's rope
• "You've never __ so good"
• Tired of everything