One of the things that I have heard and seen time and time again from many people with ADHD is that there's no point in their trying to meet expectations, because they will always fail. My ADHD husband used to frequently tell me this.  And I understand the feeling.  I've been through that experience myself, even though I don't have ADHD.  I have felt the despair and the sense of just being completely beaten down by what other people do with ease.