She is soft and kind constantly complimenting people in her mind which most likely relates to her being called 'The Pillar of Love'.
We have yet to see a different side of her or if this kind version of her is a facade.
Kochou Shinobu noted that Tanjirou was on trial, while Mitsuri thought about the potential killing of Kamado Nezuko with trepidation. When Iguro Obanai demanded to know what punishment Tomioka Giyuu would get for his role in their subordinate's mistake, Mitsuri praised his persistence, as well as Giyuu's aloofness. Later, she questioned whether or not they should make a decision in Tanjirou's trial without Oyakata-sama's input, suggesting they wait until he arrived. Shortly thereafter, she praised Shinazugawa Sanemi's increase in scars and Shinobu's sternness with the former's actions. The Love Pillar's expression of praise quickly turned to horror as Sanemi stabbed Nezuko, but just as quickly turned to mirth when Tanjirou headbutted the former, much to her mortification.