On Snapchat, your 'feed' contains only thumbnails, you have to consciously decide to consume it (per each user, although they recently changed this to an autoplay-all-others-after-first-click which somewhat undermines my point), so they pique your curiosity and tease you into consuming it.

On Twitter, Facebook, Instagram, etc. your feed is the sum of all content, so it's immediately apparent if it's empty or underwhelming.