You probably watched the aftermath of Hannah Baker's suicide in 13 Reasons Why so intently you missed hangouts with friends, dinner with family and Taylor Swift's brief cameo.
In episode 10 (Sheri's tape), a poster of Swift appeared just behind Tyler who's talking to Sheri in the Liberty High hallway. Tumblr user shakeitoff6202 posted a screen grab of the blink-and-you'll-miss-it cameo.