While I was in Japan I didn't notice changes until after we got back.
1) I all used simpler English and spoke slower.
2) I'd say 'Sumimasen' when we bumped into others.
3) I got used to squating to use a toilet and carrying around tissues.
4) Kneeling was a bit more comfortable.
5) I had a craving for green tea. Lol
6) I noticed I was speaking with a slight Japanese accent. (My host family didn't speak that much english but when I did hear it, it was always with an accent)
7) Recognizing Japanese people became second nature.
8) I take longer, hotter baths.
9) Always remove my shoes at the front door. (I had to teach my family how to do this when I got my own place)
10) I noticed my matress and pillow were uncomfortable (I slept on a futon with a buckwheat pillow. Gosh it was comfy.)
11) Almost expecting my host sister to come wake me up in the mornings.
12) Slightly bowing my head when I apologize, thanked someone or said good morning. (I did that a lot in Japan to avoid being rude. XD)
13) Craving for Japanese sweets, snacks and foods.
14) Half expecting the vending machines to have green tea and hot drinks in them.
Now I really want to go back. T-T