I just use my American passport coming into the U.S., my Canadian passport going into Canada, and my Irish passport going into Europe… Never had a problem.
No troubles at all. I think Shagnasty is incorrect.
I am a US citizen by birth and a naturalised Australian citizen. I use my US passport to enter the US and my Aussie one to go back to Australia.
My son is a dual passport holder as well. It seemed like a gift to him, to give him more choices as an adult as to where he wants to live. My son travels alone to the US and and back, and instructing the person looking after him about his dual passports never raised an eyebrow, and he’s never had a problem with it.
We moved to Israel, so I have dual citizenship, Israeli and American. My wife and kids are the same; we each have two passports. When I leave and return to Israel, my Israeli passport is stamped; when I enter and leave the U.S., my U.S. passport is stamped.
The cool thing is that when I’m entering either country, I’m always in the citizen line in passport control, so I’m always in the faster line.
I also vote in U.S. elections.