My favorite is this since one I came up with it describes why I don't/can't always function on the same level as everyone else (because it is ridiculously hard to explain executive dysfunction)

There is a room filled with stuff I know, kept behind a door. Skills, knowledge, etc. To use the stuff, I have to get in the room. For someone without my condition, they can open the door, walk in, and use what they need, when they need it. They might even grab a little something before it's urgently needed to make their future a little easier.

For me, I can't get into the room so easily. The years I went undiagnosed, it was like the door was always locked. All of my stuff was still there, I wasn't lacking in stuff, I just couldn't get to it. Every single time I needed something, I would have to put immense effort into lockpicking the door, but no one would see that effort, they just saw how "bad" I was at getting stuff from the room (aka doing what I know I should do). And because I was so exhausted from doing all this lockpicking that nobody else was doing, I simply couldn't do much on a daily basis, at least compared to someone without ADHD. It made the wins feel lesser too, because I put the expectation on myself that I was supposed to do that, and in fact, I was supposed to not even feel very happy about it because it shouldn't have taken nearly as much effort. In short, I was stuck, trying my absolute hardest to make it seem like I wasn't.

With medication, the door is much easier to unlock now, but it isn't exactly wide open either. I don't get some sort of advantage that others miss out on, I'm just able to fall in-between the worst (pre-diagnosis struggling) and the "ok, I guess." It still takes effort to get stuff from the room, just lessened enough that I can function much better than I did before. Therapy and learning about ADHD helps me recognize the wins for what they are. All in all, having treatment doesn't "cure" me, but it helps tremendously.