3 - my two favourite arcs are funnily enough not adapted by the anime, which is one of the many reasons why I dislike it so much. it's for obvious reasons The Man with the Golden Army, even though most of the fandom find it boring. but it gives a lot of backstory to Moran and explains his motivations, and it has Moneypenny, so I LOVE
the other arc I love is the Durham Date arc, as fans call it, when Sherlock casually rides the train for hours just to see Liam teach in Durham. it's an important character moment for both of them and a true crime that the anime cut it. at least the musical gave this arc the spotlight it deserved
10 - I did get into the franchise through the anime. it was new on Crunchyroll, it said Moriarty and Sherlock, and i love detective and SH stories since I was a little kid. without knowing the manga, the anime is okay, it got me hooked after all, and both openings are AMAZING!! but they cut so much,
so since I read the manga and watched the musicals, I can't go back to the anime ^^" like, even the character voices in my head are those of the musical actors, not any of the anime VAs