I get bored easily too. I couldn't tell you how many times I have spent hours getting a household, story, and world set up, only to get bored.
I agree with everyone saying try a challenge. One of my longest running saves started off as the "I'm a Lover" challenge but when I got to the second generation, I was so attached to the sims. I couldn't bring myself to follow the rules. That save file has a few firsts for me. It was the first challenge I had tried, the longest lasting save, and the first time trying rotational play. Even though I quit the challenge, it sparked a lot of other ways to play. I haven't played that family for a while now (mostly because I've been building a lot) but it's still my go-to file.
I'm not really a challenge player but sometimes I'll check them out just to spark an idea. The ones that require certain traits or aspirations may help, even if you don't actually do the challenge.