The English word "interesting" translates into Japanese as "omoshiroi." But Japanese people say "omoshiroi" when they think something is actually interesting. From years of interaction with speakers of British-English, I gradually leaned that their "interesting" is not always equivalent to Japanese "omoshiroi."
Here's an example. One day, a student who had been proofreading a scientific thesis written by a Japanese person told me that its English had lots of problems in accuracy. I asked him, "But how is the content itself?" Then he faltered in speaking and replied bewilderedly, "Uhh... omoshiroi." Well, his expression and "omoshiroi" could never harmonize in Japanese. But it was "omoshiroi" for me to learn how the English word "interesting" could be used.