Or Mostly Done

I make mistakes often these two words “almost” and “mostly”. My husband asks me ” How are you?” I say ” I am almost good. Thank you” He says “Oh! No….”   I mean I am 90% good. Why dose he say that ?

He told me “Almost good = not good” “mostly good = good”

So The Title “Almost Done = my work is not finished yet.”  I understand this, But “Mostly Done = my work is not finished yet.” .  I think the situation is the same but the feeling is different. Isn’t it right?

So confusing…