I am 62 and have never been diagnosed with ADHD, but so much of what has been written here applies to me. Self-sabotage, procrastination, and more procrastination, super focused on things to the exclusion of what is going on around me. My kids laughed at me as never finishing any projects. I have boxes of unfinished sewing projects, crafts and books bought for other crafts and nothing completed. I feel like a failure. Someone mentioned housework. Unless I have impending company, I can stare at housework and go outside and ignore it. I need a deadline that is about to expire to get anything completed. Once in a while I surprise my self and finish something!
But ask me to help someone else and I am all for it. I just have no self motivation. Very sad.
Thanks for all the responses here. Very helpful.