There shouldn’t be buffs for grapes only, mailing and flowerpicking are completely ignored because of how slow and the less pay it is. The only job that is fast and less time consumping is making pizzas because of how fast you can get gralats in a short period of time. For mailing you’ll get at least +15 gralats for each mail you post, then you’ll have to run back to a post office and get assigned to another.