What “buff” means
In gaming language, a buff is an effect that improves a character, item, ability, or statistic. It might increase strength, speed, defense, regeneration, accuracy, or some other useful property. The term is especially familiar in role-playing games, MMOs, strategy games, and competitive games built around changing states and interacting systems. A buff can be temporary, permanent, earned, granted, stacked, timed, optimized, or countered. That vocabulary is part of why the word works so well on a hat: one short term implies an entire system of rules.
The joke is a status update
The second word turns the phrase into an event. Acquired suggests that the upgrade has already happened. The wearer is not asking for a boost; the system has posted the result. It is deliberately deadpan, like a game interface reporting something important without celebrating too much. That understatement is where much of the humor lives.
Why wear it?
Because improvement is a language shared by gamers, programmers, engineers, athletes, students, and anyone who enjoys systems with measurable progress. It can mean the literal gaming reference, but it can also mean a new skill, a solved problem, another semester finished, a certification earned, a better build, or simply waking up with more experience than yesterday. It is a nerdy victory message without the victory speech.
Wear what you know.
You are not wearing a random graphic. You are wearing something you know, understand, believe, study, build, play, or find worth thinking about. That is the idea behind every NerdWear Expression.