Well, on my machine, /bin/false is program that appears to do nothing. It's a binary so, to see exactly what it does, you'll need to get the source code.
And this from the man page:
false - do nothing, unsuccessfully
false [ignored command line arguments]
Exit with a status code indicating failure.
So, if it does nothing unsuccessfully,
does that mean it actually did something? No wonder they say programmers are weird.....
Seriously, what I take away is that a user logging in who is assigned "false" as his/her shell is politely informed that he/she cannot run a shell.