Characters
I don’t need to be lectured by you. I was out saving the galaxy when your grandfather was in diapers. Besides which I think the galaxy owes me one.
— Kirk · Star Trek: Generations

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker refuses to be lectured by someone much younger, boasting of long service saving the galaxy long before the listener's family was grown. They add, with dry entitlement, that the galaxy owes them a favour.
Context reviewed