My favorite and most memorable sims are ones who’ve either had a really interesting story (whether I made them that way or they developed that way) or had an interesting combination of traits. The cookie cutter happy ones are fun, but they’re much easier to let go of or stop playing. I love giving my sims negative traits - I have so many paranoid, erratic, jealous, and gloomy sims just living their best lives.
For example, my merman sim Kane is gorgeous, but he has kids from five other sims (two mermaids, two island elementals, and the sim whose fiancé he drowned). He is a super sweet single dad and supports his brood solely by diving for seashells; he’ll probably raise all his grandkids, too, as the girls aren’t interested in family life, but like to reproduce.
My gardener sim Anna was shaping up to be kind of bland, but the townie I picked out for her to marry was kind of a mean guy, so she showed up to the wedding pregnant with Father Winter’s baby and fed her husband to her cowplant not long after. Her story took that particular direction because as a kid she caught a cowplant berry, so I decided that started her interest in gardening; the Father Winter thing came after she autonomously started kissing him one random Winterfest before she moved out on her own.
Even the one family that I play with a mostly vanilla suburban life spent their honeymoon skilling up with the help of a spellcaster in exchange for their firstborn kids. So now they have a couple of random kids adopted out to townies that they never see. And even Charlotte spends a lot of time frustrated because she has the ambitious trait but is at home with the triplets and the bonus baby (some mccc settings made it so that when they wandered upstairs on their own right after the triplets were born, little Rhea followed immediately after). Her husband is always jealous too, which is kind of fun because they’re my sweetest, most loving couple.