Rule of three is also aesthetically pleasing, and it’s enjoyable and/or funny in stories. Often with gags, there are three. Two for the setup and to establish pattern, one for the payoff.
thank u, hexedUsing lists of three is not an "AI tell." It's a common trait in human writing because our brains biologically want to make sure there's always one thing to marry, one thing to fuck, and one thing to murder.