When I first started knitting I used to think. Why do I need to weave in the ends. Why can't I just knot the end and have that be good enough. I would like to present these two pictures as examples of why. I loved this hat, and I could probably repair it, but I think its just going to serve as a lesson learned.
It is necessary to weave the ends of your knitting so that this doens't happen. I knotted the end of this project because I didn't know any better and this is what happens when you do that.
The knot will eventually come loose. This hat is a couple years old, but it will eventually happen.