Getting rid of emotionally mindful 4hr buff?

if you're on pc and not against mods, i recommend you UI cheats extension.
it offers many useful tools for the game and one of them is the option to right click any moodlet so it instantly leaves

Sims get this buff for doing low intensity activities like painting, hiking, reading, and listening to music. To prevent them from getting this moodlet, switch to higher intensity activities, such as skiing, workouts, and programming. You'll have to experiment to find out for sure which activities fit which category.

To get rid of the moodlet, once you have it, keep doing the low intensity activities until you get a +10 Fine moodlet. Once you have that, your Sim will have a self-interaction to Surge an emotion of your choice, which includes all emotions except scared.