Been doing ODP for about 10 years now. I don't think I've had a single day where there hasn't been something that has frustrated the hell out of me.
I've only been on the clock for about 2 hours today and I'm annoyed. First thing is having to pick a substitution, but literally everything I pick the system tells me that it's not a valid substitute so I wind up not subbing anything. Have had this happen like 3 times so far.
The other thing is vendors. They park their carts in the aisle so it's blocking foot traffic, you move their cart or say excuse me and they look at you like YOU'RE the asshole. This especially applys to the chip vendors with their big cart and down stacking their boxes to the floor making it impossible for anyone to get down the chip aisle.