Maybe they are tired. Maybe they have an invisible health problem that we don't know about. Maybe they were up most of the night with a sick child. Maybe they really don't like shopping and it's the only way they can motivate themselves to get through the store. Maybe, maybe, maybe.
Maybe they don't like the way I can be in a little too much of a hurry. Maybe they don't like the way my son can get whiny if he's shopping with me and doesn't get his way. Maybe, maybe, maybe.
The street goes both directions. Or the aisle goes both directions. And I'm as snarky as the next person and would maybe notice something like that (I haven't, BTW), but I'm not going to give it a second thought once I'm out of the store. And trust me, I have plenty of grocery store annoyances.
I do have sciatica pain and when it's flaring it's no fun. I don't lean on the cart, but I do like having it there for backup. It helps having it there to hold onto.