I only just learned that level 10 scientists can "perform experiments".
There are lots of possible effects, the best of which are moodlets given by using an object like "Winner" Or "pumped" or etc. If you experiment on your fridge, counter, food processor, stove, dining table, and dining chair, you could boost your sims mood before work by over 100 points just by doing daily stuff.
But two of the negatives cannot be undone. All others can be gotten rid of and you try again. FIRE AND VANISHING ITEMS.
So yeah now they won't happen anymore