Never minded either RDC or store delivery work tbh, as already mentioned, if someone wants to pay me to sleep/drink coffee/browse the web, happy days!
Store delivering can be a ball ache but certainly Tossco stores are generally easy enough, if the yard is tight I get them to move whatever is making it tight (wherever practical) and always have a good crack with the staff.
You encounter the inevitable miserable sod from time to time, I’ll just enjoy reminding them that they are stuck there day in & out, I’m not! 
I think the majority of the issues with supermarket or indeed any other work is often down to your own mindset.