(M18P02) Unnecessary Things that I have the most

Every time I travel, I tend to forget to bring the global power plug adapter. I was cleaning up the house today and found more than 10 of these. Considering how expensive they can get when bought at airports, I realize that is a lot of money I wasted.

Don't even get me to start on Tupperware!
 
What are the unnecessary items that you have a lot of, and why?