Which is the case anywhere you go, really.
At each school, there is a staff member that the other ALTs and I call the “tea lady.” In Japanese they’re called the 校務員, but since one of their duties is to serve tea and drinks to the other staff, we call them “tea ladies.”
Strangely enough, the tea ladies at each of my schools are pretty opposite of each other. They’re both about the same age I think (maybe their 60s). One of them is the sweetest lady I’ve ever met and doesn’t complain about a thing. The other one is one of the rudest (probably THE rudest) Japanese person I’ve ever met. There’s a long background story that I won’t go into, but for some reason she simply doesn’t like me, despite that I’ve never done a single bad thing to her. When she serves drinks to the other staff, she won’t give me anything. Yesterday was a little different though: She actually did give me a drink, but there was no ice in it, though I could clearly see that the other staff had ice in theirs. Not to mention that she kind of shoved the drink on my desk and walked away.
This, however, does not bother me too much. It’s annoying, but here’s how I see it:
1. I have no problem getting my own drinks. In fact, I bring my own bottle of Aquarius to drink after my biking commute anyway. If I need something else, I’ll get it myself in the kitchen.
2. With the amount of money I make, I don’t mind putting up with one rude staff member in an entire school three days a week.
3. I’m willing to bet that the children like me more.
On top of that, I actually find her behavior quite entertaining. It gives me something to talk about, and the other ALTs that have dealt with her know exactly what I’m talking about.
You can’t expect everyone to like you when working anywhere, especially overseas. It can be especially difficult when that person has been working there longer than you have. Just don’t let it bother you too much, because you quitting is probably what they want.