There are three doors, one has a prize and the other two are empty. You pick a door (say, Door 1). Monty then says that his assistant will move whatever is behind Door 2 (if anything) to Door 3. He then opens Door 2 to show you it is empty. Would you switch to Door 3? Of course you would.
But Monty’s assistant is lazy, so instead of moving the contents from behind one of the closed doors to the other, he just asks Monty to open the one that he knows is already empty. The result is the same.
Unlike what the OP stated, the key is NOT to list you phone number as an SMS 2FA recovery option. Only use the non-SMS options (e.g. app-based recovery, Google Authenticator, recovery codes). Adding SMS as an option makes your account less secure, not more.
Unfortunately, most sites do not allow you to turn off SMS recovery even if they offer other 2FA options.
Security is only as strong as the weakest link, and SMS is very weak.
Stop calling it “rideshare”. The driver is a not “talking a ride” and “sharing” it with you. They are a paid driver. This is a taxi service — not a carpooling service.
These are the course notes for CS 206: Computing with Symbolic Expressions taught by John McCarthy at Stanford University in the 70s, 80s, and 90s.
I printed this copy in 1984 while working as an intern for Nils Nilsson at SRI's AI Center.