Sifting flour seemed pointless to me until a batch of lumpy cake proved me wrong
I thought skipping sifting saved time with no downside. My cakes came out dense and had dry spots. That lumpy cake was a mess to eat and serve. Watching a video on proper mixing showed me how air gets into the flour. Now I sift every time, and my bakes are way better.
My friend Sarah tried skipping sifting for her weekend pancakes. She ended up with these weird, bitter bites that made her whole face pucker. We figured out they were little clumps of baking powder that never got mixed in. She called them "surprise crunchies" and it totally ruined breakfast. Now she just does the extra step because nobody wants a mouthful of bitter powder.
Sifting does more than add air; it blends baking powder and salt into the flour so everything bakes evenly. @betty213 had it right with the teeth comment, but it's also about taste and texture in every bite. Without sifting, you might get bitter spots from clumped baking powder. I learned this after a batch of cookies had weird salty patches. Now I see sifting as part of measuring, not an extra step. It really does make a difference in how good the bake turns out.