Measuring Tape Metal
Every single one of us has used a measuring tape for one reason or another. How could you have missed out the small metallic piece at the tip? They added it there so that you can wrap it around a screw or nail when no one is around to help you. Aside from that, the serrated edge makes it easy to leave marks.
Pen Cap Holes
It might seem like a design error, but there is a good reason for the existence of your pen cap holes. They actually added it so that anyone who swallows it would have no problems breathing! It makes a lot of sense. After all, a lot of people have this habit of putting these pen caps in their mouths!