I Am 100 Percent Going Insane

This is what my life is like; every single day I have to talk to a crazy person, and even the most sound person would go insane talking to them. Here's an example conversation, imagine it speeding up dramatically and gaining more tension with each exchange.

Me: (casually) what are you drinking?

Them: Oh It doesnt have lemon

Me: what kinda tea is that?

Them: Not yours, Its not sweet I didnt put the sweet n low in it

Me: (why?) I have some sweet tea in the fridge...(gets cut off)

Them: Im used to the lemon flavor, I dont like it without lemon

Me: You or I could buy some lemon at the store nearby.

Them: Lemons have been getting really bad bacteria, you can get bacteria from the rind.

Me: you dont use the rind, you should be ok.

Them: (Walks away upset in a hurry and doesnt go to the store)

Me thinking( she's gruding me for not buying the more expensive lemon flavored tea but won't come out and say it, or except any alternatives or take responsibility of getting her own tea, which she did anyway but not the type of tea she likes.)