I've had bad days. I still managed not to be a net negative on my environment. Why can't you? Why can't other people? From my perspective, how you behave when you're having a bad day is the real litmus test. If you're still a decent person then, then you actually have values you care about, that you don't just follow when convenient.
Theoretically, in this case, the agonizing "It's pouring rain, blowing cold wind in your face, kids are screaming and hitting each other, you stubbed your toe into cart and generally just having bad day" scenario making any man unable to manage the extra-harrowing effort of directing a cart a few meters into a designated space.
