I learnt to play Scrabble with my grandma in the 80s, and for years she was the only person I played against (I didn't have a board). She played the rules she was taught when she first learnt the game as a young woman. One such rule was that you had to play all your tiles contiguously. I.e., you can add PEA to an existing L to make PEAL or LEAP, but not PLEA because the latter would involve splitting your placement either side of an existing letter.
Of course, this is not a rule. But has it ever been? Had she misremembered the rules, or just not reread them since the 50s?! I would be interested to know.
I still play this rule sometimes in memoriam, and it makes for a different challenge.
Her last ever word (played in 2007) was LEGACY for 42 on a triple word. She won the game.