Ah sorry for the delay, in transition between my old computer and new one!
Hmm I don't see many people talking about it, but I think my favourite book is The Emperor's Soul. Warbreaker, Words of Radiance, Oathbringer, and Bands of Mourning are all amazing reads and are definitely my favourites most of the time, but having recently listened to The Emperor's Soul again and remembering my first time reading it, having such an emotional connection, it reminded me just how amazing it is.
And as for theories... yes! I've definitely got some about Lightweavers, Forgers, the uses of Fortune early on in the Cosmere by the Shards, in particular between Ati and Leras. I've also got all kinds of ideas with regards to Cultivation and Honour, and Aona and Skai, separately. Plus I'm *confident* there's something going on with Ambition behind the scenes; definitely its influence can be seen, as I'm sure all shards you could say can be. The shards that haven't been revealed yet, while I'm sure they're kept strongly guarded secrets, I'm also certain they've been hinted at a lot more than people might realize. I'm pouring through Words of Brandon right now so I'm sure I'm in for a wild ride and will learn much more going forward!
P.S. as for personal interests, I'll just say I'm most like the Purelake; an expansive, yet shallow lake; though as I learn more I'm sure my depth of knowledge will one day match its breadth (except music; though not the most practically applicable of skillsets in a cramped apartment xD)