I couldn't believe it when I learned about the circle in the middle of Glad plastic lids. I'm not making advertis to this company, but because these containers are popular in many houses and I'm pretty sure you do not know the utility of this circle.
I have never paid attention to it, it looks like a "decoration", but it's really useful!
The small circle is used to hold the smallest containers in the cupboard! Dressing, dip, humus, condiment ... Any food eventually you do not want to mix!
Instead of using the small lid supplied with the small containers, just use the round lid and that's it!
Did you know that? I am amazed to have spent many years using these containers without knowing it! As they say: everyday is a school day!