What Is ‘Challenge Accepted,’ Exactly?

Some recent examples include: the pillow challenge, which saw celebs posing with a pillow belted to their front, cheekily naked but for their downy shields; the 2009 vs. 2019 challenge, which really highlights hotness accumulated over time; and this week’s challenge, which appears to ask women to post a flattering black-and-white selfie from their camera rolls.