Third Wheel
Narrow sidewalks are the bane of existence. They prevent proper conversations from ensuing by forcing groups of friends to forgo walking side-by-side because … narrow. This is especially awkward if you’re in a cluster of three. Only two of said group can feasibly walk together while the third person “third wheels” it in the caboose.
It’s like being the third wheel in a couple. You get to sit quietly off to the side while Megan and Barry are being all cute and unbearable. No one likes those couples. Identical situation here. Now, Megan and Barry can hold hands and explicitly divulge details of their trip to Cancun while you listen … in the back.