https://blogs.scientificamerican.com/roots-of-unity/ping-pong-for-introverts/

Ping-Pong is great, but there’s a catch: you have to play with someone else. What is a committed introvert to do?

You could always hit the ball against some fixed object, but as Mitch Hedberg observed about tennis (easily generalized to other hit-a-ball games), you’ll never be as good as a wall. Demoralizing! You could play a Ping-Pong video game, but what if your virtual opponent is too good or not good enough to have a good game?