I'll admit it - I used to be one of those people who didn't believe ADHD was a thing.  This idea persisted well into my Ph.D. coursework.  During a discussion in a course on ADHD in my doctoral program, I defended this idea: 

"I can't sit through a movie because I get bored, but that's totally normal!  I don't get much enjoyment from reading because my mind drifts and I end up reading the same sentence over and over, not absorbing any of it, but that's totally normal!  I hardly ever paid attention in school; I was constantly daydreaming, but that's totally normal!  I fidget constantly, but who can sit still?  It's totally normal!  I always wait until the last minute to do things, but that's totally normal!"  

It was at this time that I noticed the looks on the faces of my classmates and my instructor - they were aghast.  

"Um, actually, none of that is normal, Shannon.  You may want to  make an appointment at student health and talk about this," my instructor told me.  And then it was I who was aghast.  "You mean, these things don't happen to you guys?  These things aren't true of everybody?"  It was then that it dawned on me...maybe ADHD is real...and maybe I have it!  

A visit to student health confirmed this.  ADHD is real, and my experiences had not been the same as everyone else.  I started medication for ADHD, and it was like someone flipped a switch in my brain.  I was finally able to experience what everyone else did.  I couldn't believe the difference, and was sad about all that I had probably missed out on because of my inability to sustain attention.  

I'd been able to compensate with coping strategies, though many of them were unhealthy.  Breaking those lifelong habits has been difficult and is something about which I continuously remain vigilant.  I still don't go to the movies very often, though.