Ever wonder why a tape measure hook wiggles when you press or pull on it? So did George Vondriska. He found out that the hook slides in both directions to accommodate for the thickness of the hook, so you receive an accurate measurement each time, no matter whether you are pushing or pulling against an object.
The other thing to mention is that dropping the tape measure is almost always a death knell for the accuracy of the tape measure because that end will bend.
And if the amateurs let a tape retract from too much a distance, the impact on the hook and the end of the tape will eventually throw this off. I cringe when I see this happen, and end up educating the culprit.
I remember when I got my first tape measure, a long, long, time ago, I thought it was broken so i tightened the thing up, no more wiggle. Measurements always a bit off. Figured it out later in life. So lessen learned.