We each had "one-stop sets." It was all rather ridiculous (and of course no one really laughed) but it actually was a strangely valuable learning experience. In that kind of situation, you better bring some energy and your jokes better not be wordy. Get to the point quick or don't bother. And it certainly makes a normal audience less intimidating. What are they gonna do? Be more apathetic than the crowd on a midnight subway car? Highly doubtful.
Related: Insight on connecting with an audience from a subway musician:
When you play on the street you can't approach it as if you are playing on a stage. Busking is an art form of its own...You have to relate to the audience and be a real people's person. You can't hide behind your instrument and just play, with an invisible wall between you and the audience, the way a stage performance is conducted. In busking you use the passers by as if they were paint and your music is the paint brush - your goal is to create a collective work of art with the people, in the space, in the moment with you and the music.
A busker is someone who can turn any place into a stage...As a busker one needs to interact with those around, break walls of personal space, and lure people into a collective and spontaneous group experience on the street, in the moment, with you. A bad busking act is when the performer doesn't make an effort to connect with the audience. Like musicians who play for themselves, not acknowledging the audience, just burying their heads in their instruments.