I think we've all had one of those days. You're cranky, don't feel well and things just aren't going your way. You try to ignore it and then some small inconsequential annoyance pushes you over the edge.
Well that was me on Day 54 of our "Big Trip." I wanted ice cream and a chain restaurant Lotteria (akin to McDonald's) had a large display showing a variety of delicious ice cream you could order. But, they didn't actually have any ice cream! That was it -- inconsequential annoyance that led to my meltdown and my desire to "go home" where I could eat all the ice cream I wanted.
This happened to me occasionally in Korea. I was having a bad day and suddenly some small cultural difference irked me greatly and suddenly I wanted to "go home." It passes and I'm very happy to be where I am. Although I'm still in the mood for some ice cream!