Frustrating

Colton is starting to have some jealousy issues with Connor. I'm assuming its because Connor can now say a few words and can now walk. So, the other day in the car, Connor was singing "lalala" "lalala", and Colton says, "Connor, you can't say lalala"! And I said, "Colton, yes he can. Connor can sing if he wants." Then, Colton muttered under his breath, "Well, that's frustrating!"

Seriously, does anyone else know of a two-year old that knows the word frustrating?