When my daughter was small, before she was in school, it was just the two of us alone together all day, so I'd often take her on these marathon shopping days. After about three times in and out of the car seat and the cart or stroller, she'd get really testy. But I found that if I took the time to stop, breathe, and get down on my knees and just hold her, hug her, love on her a little, she'd be okay.
That's how I feel sometimes. If someone would just love on me a little...I can make it through whatever marathon of daily bullshit I have to deal with.