Peach is a more kind character than most others. She is criticized much for her habit of "helping the helpless" as many people have become familiar with. This trait leads her to accidentally giving Gree her autograph. She also tends to shower other characters with compliments, and is very good mannered. Many non-MVPs in Pictochat seem to have an intense crush on her.
In contrast, Peach is very emotional. In the household, she is seen to throw fits at Rosalina and cry hysterically when she gets injured. She seems more outgoing when she's out in public, strangely shying down a little when she is with her roommates.