Well it is a behavior disorder. If you don't have disruptive behavior, plenty of other psychiatric conditions cause the same or worse executive dysfunction (e.g., bipolar disorder, major depressive disorder) and the same or worse social anxiety and rejection sensitivity (e.g., social anxiety disorder). Let's not pretend like ADHD isn't difficult for others around the individual to deal with; it is, by definition, if someone has it.

Ask me if you'd like sources for any of the above.