I don't recall seeing it blatently said that 4's suck at completing things... but I did see a video once that emphasized it and it made me wonder about this.
I always start things with great intentions toward finishing them but I burn out quickly. I don't know how much of it is the INTj 'brainhoppin' and how much is the 4 but it sure does tick me off. At times I REALLY want things, and I KNOW that I could do it... and then the doubt sets in and the excuses and suddenly I'm sick of hearing myself. So then I get motivated again. Its a self-defeating cycle that never accomplishes anything. I am SO DAMN TIRED of living like this! I used to be so driven! I used to set my mind to something and come hell or high water I would make it happen. Somewhere along the way I decided that trying, that working for goals wasn't worth it. A lot of things that I had planned out in my INTJ brain that I thought were fool-proof blew up in my face and now its as if the confidence that I had is gone. Its been gone for years now and it pains me to remember how I used to be.
Does that just happen as you get older? You give up on dreams and on making progress and just accept where you are?
If any of ye other 4's have this problem I'd love to hear from you. Or even anyone who has felt this way and found a way to believe in their ability to make progress again!