According to Jim: Season 8, Episode 10

8 - 10: The Meaningful Gift

Andy, desperate to impress Mandy with the perfect birthday gift, turns to Jim for advice. Jim counsels against givivng fancy jewelry, urging Andy instead to give a sentimental gift to win her over. But Andy's recollection of what has meaning to Mandy is way off base, and instead of being pleased with the gift, she thinks he's cheating on her.