Why do we torment ourselves with sizes?

Our goal weight often involves a specific clothing size. We focus on the single digits or we want to be in a size 4 or 6. But here's an interesting story:

Today, I went to a cheap second store that I like. I bought 4 skirts. None had the same size. One was a size 4, another 8, another 12. Did I gain or lose in those 20 minutes I spent in the changing room? Of course not! So why do we torment ourselves with fitting into a specific size?

Instead of focusing on numbers, we should focus on how feel. And never should we let a clothing size ruin our day!!!