There are a few words in Japanese that I always get tripped up on because their English is the same or similar. For example, in Japanese they say [Noun] no sei for being the fault of that person or thing, but [Noun] no okage for being 'thanks to that person or thing'. Both equate to the English 'because of', but whether it is a positive or negative connotation changes the word that comes after it.

Recently I have been getting tripped up on the difference between Ondo (temperature) and Taion (temperature). Ondo is to do with the temperature of something, and Taion as body temperature. I have a tendency of saying Ondo when I mean to say Taion, and it confuses people, sort of like "did you measure the temperature?" when you mean to say "did you take your temperature".

Then, one more that I really should have gotten a handle on by now seeing as I learned it about 20 years ago is that Japanese has different verbs for wearing things on different parts of your body, i.e. when you say 'put on a jacket' (kiru) and 'put on trousers' (haku), the verb changes. If I'm not thinking, I say '[verb for put on trousers] that jacket'. It must really confuse people, as much as it confuses me.

But the thing is, all languages have quirks like this. If you want to master the language, or to even get a handle on it, you need to be aware of these things, there's no way around it. If you change your attitude from one where 'this language is strange', to an attitude of 'let's master this', the difference is stark. Soon you forget that these quirks exist, and you can get on with learning other aspects of the language that give you a better command overall.

(one other one is how there are many different ways to count things in Japanese, for example, cylindrical things and animals or sheets of paper all have different ways of being counted, this takes a while to get used to as well).