Do other people mistake your ethnicity?

I'm sure many of us here have experienced strangers mistaking our ethnicity and I'm interested in what you were mistaken for, and your reaction to it. Do you guys feel flattered, insulted, or confused?

I'm Japanese/Filipino and I've been mistaken for Chinese, Vietnamese, Korean, or Latino because I live in a very multicultural area. At my job, I sometimes have older Chinese customers talking to me, and I feel disappointed in myself for not being able to understand them. Being spoken to in Spanish really surprised me the most because I don't think my facial features look Latino, or maybe it does?

And how can you guys distinguish one asian ethnicity from another? I find it hard to tell asians apart just from looking at them. I can only tell from the language they speak.