You had a nice idea for a joke, but your presentation did not portray it as well as could be.

The arm animation was too slow and sluggish for the intensity of the talking. Also, doing a quick cut of at the end of the last scene would have kept some of the punch line feel there. As it was, the fade out after three seconds of still frames lessened the whole impact of the joke.

But! You still had decent animation, and your voices fit the characters. And your set was simple, but still had some small details that were nice to see. Your skills have been progressing very quickly since your early films, so keep it up.

Not bad.  The animation, while it could use some tightening, is pretty smooth.  There is some flicker, though, particularly in the "glass" window where your hands are reflected in, and the lighting is a bit flat and yellow-ish looking (though nothing too bad).

Cinematically speaking, I think this could use some improvement.   Perhaps I'm being overly picky, especially given that this is only a 20-second short, but the camera angles are a bit bland and boring, if I'm perfectly honest, and the joke (whilst funny in of itself) kind of falls flat in its presentation.  You're always keeping the characters at arm's length from the viewer, which makes them feel detached.  The final shot in particular feels very awkward since you're using a very wide shot and the camera is angled downwards for no cinematic reason.    It would have been much better to use close-ups when the characters are speaking, in my opinion, as it would have made the punchline more lively instead of making it feel more like an afterthought thrown in.

Sorry if this a bit overly detailed, but I hope this helps!