@haneul Whoops, saw you commented right as I was typing up my own reply. I used to delete all premades too and fill my households with as many interconnected sims and stories as I could come up with on my own, so I totally get that. Then I got too many packs and too many worlds and it was too hard to fill them with all my own sims so I started using premades for my stories sometimes or making more connections and relatives for premades when I got ideas for sims (Like giving Penny Pizzazz a sister named Polly Pizzazz haha). But I totally respect both (or any!) way of playing and I do think it's very cool to have the option to both and to have more than one save going too to explore all the options.
One of my reasons for starting this thread too is that I've been playing errands in Henford-on-Bagley recently, and if you take the time to read all the pop ups that come with those mini quests, they really are so thought out and all the residents are so connected that you could have a whole story just with all the information and backstory given with those. It made me curious to see places that other people find lore in the game (like that Princess Cordelia backstory mainly told in item descriptions). It just all fascinates me so much!