Monica Celeste has always been called the most artistic by those who like to label the Septs, and it's true that she does spend a lot of her free time doing artwork of all forms. Drawing, painting, and writing are her favorites. Two of her other favorite hobbies are cooking and gardening, which you could also call as "creative" in their own way. She just loves producing something to show for her time, whether it's her own AP Art showcase in the school lobb or her made-from-scratch apple pie—a legend in the Carlson family. Even now that they're older, people say they see in her a certain something that reminds them of a cute little kid, even though they certainly wouldn't call her immature—maybe it's just that she still enjoys coloring pictures with crayons when she wants to unwind.
Though she's generally cheerful, one thing that always throws her off is conflict. She hates arguments and tension between people more than anything, even if she's not part of it. She's a lot like Megan in this respect, but Megan tends to avoid conflicts while Monica steps right in and tries to work things out between people. (Megan is also shyer than Monica, which must be why Monica became "the fighter for peace" and Megan simply "the always peaceful.") When Mary and Melissa would argue, Monica always would try to reason things out for them (often to their annoyance, because they just wanted to work things out in their own noisy ways). Usually, though, Monica succeeds when she tries to work out a conflict, because she simply won't rest while one is raging, no matter how much it drains her (or others) to work it out. All of this lead to her being nominated to be a peer counselor at her high school. Some call her meddlesome, but most find it reassuring to have Monica around.