Being an introvert, you might go “Okay, well this thing that takes an hour is about the limit of my Ability to People for the day. I won’t have the energy to do this other thing later without a break.”.
ADHD is “Well my appointment’s at 2pm, but I should probably plan to show up early just in case, and driving takes 15 minutes, so I should round that up to an hour, and I need at least 3 hours to get ready in case I get distracted, so I need to get up at 8, and I can do Nothing Else.
Bonus points if you manage to fuck over your sleep schedule the night before because you’re feeling anxious about getting to the thing on time.
(If that sounds exhausting, it really is.)
You hyper-correct because you’ve been late to so much shit, because Time Blindness is a big part of ADHD.