Why Does My Mother Compare Me to My Cousin?
Comparison is the oldest motivational tool humans have and it has a terrible success rate, which has never slowed anybody down. It keeps coming because of: 1) social proof used as leverage, since pointing at an example is much easier than making a request 2) reflected status, because your cousin's win is currency she can spend with her own brothers and sisters 3) the contrast effect, because holding you up next to something makes any gap look larger than it actually is. You are not being compared. You are being used as a number in somebody else's conversation.
What is actually happening
The example replaces a request
Her siblings are the real audience
Contrast makes gaps look bigger
The comparison is not about you
The real gap
Ask who else she has told about your cousin lately.