The 100K number seems to be an important milestone for Graal.
100K kills you get a 100K kill hat, same for Spars I think, you also get access to buy weapons the rest of graal cant get.

My question is, why cant there be achievement hats for performing jobs 100K times?
Unique, job themed hats for 100K trash, 100K mushrooms, 100K pizzas, 100K mails, 100K rocks, 100K shells, 100K flowers, 100K car missions

This will probably derail from the hat question, but maybe getting 100K of a job could get you special access to a better/alternate skinned mushroom knife, pizza board, drill, shovel, basket, and IDK what for mail (a car that looks like a mail truck?)