When you do something nobody did before or are faced with a moral dilemma you've no prior experience with it's often unclear whether what's "Good" and what's "Bad" in some general sense and so the reaction may be based on "vibes".
Dick Fosbury's weird jumping style? No rule against that, but equally the committee could have seen it and said "No, that's not OK" and forbidden it by the next event. They did not, Dick seems like an athlete, this is a new technique, fine by us - and today everybody serious uses this style (the "Fosbury Flop") or one based on it for jumping.
Modern Contract Law mostly comes back to "Carlill v Carbolic Smokeball Co" in the 19th century. This is about a quack medicine (Carbolic Smokeballs don't prevent Influenza) but the legal question was: If you specifically advertise that if people do a thing (use your Carbolic Smokeballs) and an event happens (a customer catches Influenza, "flu") you will pay them a lot of money (£100 in the 1890s) - well can the advertiser say they didn't mean it when asked for the money? Mrs Carlill seems like a nice lady, everybody hates people selling quack medicine, so obvious Carlill wins - but setting out explicitly why she wins forms the basis of an important part of modern civil law. That advert is an Offer, the choice to buy and use the Carbolic Smokeballs was Acceptance, she caught flu, therefore now Carbolic Smokeball Co. owe Mrs Carlill £100.
If you've ever heard about why people would buy a seemingly worthless thing for $1, or about the peppercorn rents, or wondered why you're told you "agreed" to a bunch of legal stuff you don't care about and haven't actually read - that all comes back to Carlill v Carbolic Smokeball Co. Maybe if she'd been an awful smug Karen trying to get paid for moaning and they were selling a pretty good (but not 100% effective) cure for flu, judges would have instead figured out why she does not get paid and our case law would have turned out very differently.
[Edited to fix typo]