Did you know that your knitting has a tail?
Yup, it does.
Once you've finished putting your stitches on your needle, you will have two ends of yarn trailing from these stitches. One of these yarn ends will lead from the stitches to the ball. This is your "working yarn". The working yarn will be used while you knit. The other yarn ends will not be attached to anything. This is the "tail". The tail seems only to be around for the ride and it's not to be trusted. Indeed the tail is sly. It needs to be watched. If not closely supervised it can create all kinds of mischief.
It can make stitches disappear.
It can disguise itself as the working yarn.
The first problem can be avoided by ensuring that your tail is long enough not to pop through the last stitch. Leave a nice long tail. Unfortunately, this long tail can create the second problem. You see, it is easy to mistake a long tail for the working yarn. Fortunately, there is a solution for this problem as well.
Put an anchor on your tail.