It has been long since lost to history, but many aspects of what we think of as a modern suit in ternion society is derived from goblin clothing conventions. The inner pockets, the modern neck tie, the padded shoulders.
Even more than we do, goblins value suits as a status symbol. As such, many a dust out goblin, new to the big city makes sure that they save up for and purchase a suit as quick as possible. make sure the world knows they're the real deal. That they mean business.
Naturally, getting a suit made to goblin measurements costs more than they think, and they can't really buy off the rack.
As such, it has actually become a fashion among goblins to buy an off-the-rack suit made for a larger species and wear it anyway. Looks odd to us, but it has become a fashion in of itself with them.
Some people are even getting custom made suits made far too large so that they can affect the same look. Which is just weird.
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Got a request for Karl in a zoot suit. I went with one of the classic historical looks rather than the over done ones they use for costumes. The in-universe explanation just made too much sense to me.