[Warning: the following is my opinion, not some incontestable truth.]

It's less about bending rules and more about enforcing them by spirit, not letter.

Reusing your example: I think that you did the right call there - sure, the post doesn't "share" a cool website, but it's still about one. It might not fit the letter of "find a cool or useful website on the internet. Share it here so others Lemmings can bookmark it too.", but it's still well within the overall spirit of the community, and why that rule is there on first place.

Another example: my comms often have a rule against off-topic, but if people start some friendly chitchat in the comments (they do it often) I leave them alone. Because the spirit of the rule is to avoid content that would derail the community, and that chitchat won't do it.

You'll often get rule lawyers trying to "mmm, ackshyually, the rule says that orange socks aren't allowed, but my post has a reddish yellow sock". That's unavoidable even if you enforce rules by the letter; nothing ever written is completely unambiguous, there's always some grounds for alternate interpretations. As such don't feel discouraged by them.

Note however that what I'm saying does not mean that you should disregard the letter of the rules. Don't - the rules should be still listed in a succinct and accurate way, both to guide your comms' users and justify your actions; it's a matter of transparency. Instead edit the written rules over time, to address issues that makes their letter betray their spirit.