Just bear in mind TOS is almost 50 years old it was made in another era, where continiuity wasn't as important.
Right. I'd be hard pressed to come up with more than 2 examples where a specific event in an episode was ever referenced again. One was the two times Kirk used the Corbomite bluff. A better example is when Kirk suggested Spock use the mind meld trick to convince the Kelvans they had escaped, since it worked against the Eminians.