How do you make your game more fun/engaging?

I agree with a few people in here who were mentioning looking up challenges, I've done that myself if I've ever gotten bored and wanted to spice things up a bit. Recently I made an evil sim who had a shed out back with a secret basement room where he would lock up his victims to be fed to his cowplant. I also made him try to lead a normal life otherwise -- he had a successful career as a detective and an unsuspecting wife and kids, and there was a specific "type" of sim he would scope out to be his next victim (blonde young adult females.) Of course a lot of the fun of it came from the story I had going on in my head. :) One challenge that I've been meaning to do next time I need a break from normal gameplay is the alien takeover challenge: https://forums.thesims.com/en_us/discussion/837731/the-sims-4-alien-takeover-challenge

I am very into generational/legacy type gameplay, personally. I get so attached to one sim family and I love playing around with their genetics and seeing how the next generation turns out, so generally I can go on like that for awhile and not get bored. One thing I try to challenge myself to do with each new heir to a generation is play with different traits/careers/skills/hobbies that I either haven't tried before or haven't used very often. Creating drama can be fun and interesting as well but I tend to end up feeling guilty lol. I also love building so if I get burnt out on gameplay sometimes I'll just go on a building spree for a bit.