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But while tics aren't a reflection of your own thoughts, they can be influenced by the outside world. Ben's family finds it endlessly amusing to suddenly shout "Waffles!" because without fail, he will tic it back to them. This is a phenomenon called echolalia, and Christie Hayes experiences it, too. "It's like a game of Simon Says."

It would be great if it was always that innocent, but Ben describes it as "like having a little guy in your brain saying 'What's the worst thing we can say right now?'" For example, Sunday school was a big problem for Ben. As a devout teenager, all he wanted was to learn about Christ, but his good intentions were thwarted by stern-faced preachers who didn't appreciate him growling "Fuck me, Jesus" like a black metal singer during service. Christie had a similar problem when a college professor complained to the school about her service dog. It just wouldn't stop barking during class. But it wasn't the dog -- it was Christie.

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"Don't worry. I left him a gift."

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These misunderstandings make life a lot more complicated. Whenever Ben gets on an airplane, he has to hand the crew a note stating that he is medically certified Not a Terrorist, because on his first international flight, his brain decided that was a good time to shout "Bomb!" And though he doesn't have a racist bone in his body, he's constantly afraid to walk around in neighborhoods with a predominant minority population, for fear of inadvertently acting out scenes from Die Hard With a Vengeance.