Thanks to crippling undiagnosed ADHD (inattentive) plus insomnia, depression, and Oppositional Defiant Disorder*, I was in both the gifted and disabilities groups during my public school days.
Which lead to weird mental whiplash like being given an aptitude test battery and scoring post-college level on almost everything with a reported IQ three points short of genius (which is how you know that test is bullshit, ha), except the reason I was given said test was because I was on the verge of flunking out of high school due to being incapable of doing any work.
I'd have killed for the ability to simply focus and get things done. Intelligence is nothing without a matching work ethic, or whatever you want to call a functional dopamine system.
* Mini-rant: I'm half-convinced this so-called "ODD" was solely the result of a lack of sleep. I remember nearly passing out every day at school, and the main symptom I display when tired is a lack of patience for everything when I'm normally the most laid-back person imaginable. The instant I started college I became a perfect 4.0 student, and the only major difference from before was that I got to start the day at a sane hour.