For Sara Benincasa, 33, a comedian and writer in Los Angeles, that friend is Heather Fink, whose work as a filmmaker and sound technician takes her to exotic locales, which she dutifully records on Instagram.

Ms. Benincasa recalled being at a CVS drugstore, waiting to pick up her refills of Prozac and Klonapin, when she began scrolling through Ms. Fink’s feed, which is updated frequently, especially when Ms. Fink is jetting around the world.

“She’s in Cannes, she’s in New Mexico. She’s in Abu Dhabi for a film shoot. She’s going to Holland. She was just at Jared Harris’s wedding on a yacht in Miami,” Ms. Benincasa said. “I’m standing there in my stained sweatpants, I was thinking, ‘I really need to up my game in life.’ ”