Yes, indeed, you're not smart, but you're wise, for thinking of something even the smartest guy on earth wouldn't say.
-Duolingist(made it up)
Unless someone called you smart, and you ask them why using "why am I smart?"
Psych! Trick question. I'm not. You probably are, though. (Also, you guys have no idea how many times I got frustrated after putting in "Why am I fat?" Proof I'm not smart AND proof that I'm not happy with my life choices. Yikes.)
I fear that I will one day fail to compliment someone by saying they're fat instead of smart
No, in English when asking a question, "I" must go after "am" not before like in a statement. With most questions in English word order changes.