It's difficult work, moreso than you'd guess, and they ask an awful lot of it from you. Winter is steady 14 hour days, 6 days a week.
Summer is more like 50-60 hours a week, and they have an exaggerated sense of what constitutes a fair work day so it's not just long hours, they're whipping you on top of that.
But it pays well, it's satisfying, it affords you the status of being a mailman, and let's be honest, you have no other decent choice without a degree.
Prepare to be perpetually exhausted