I've never used over-emotional. Here's why:
A 25 percent increase in moodlet to me isn't needed since well rested + good meal + Squeaky clean + Having a blast makes your Sim pretty much as happy as can be. Also, in the early stages, I push my Sims to and past the limit often. I exercise long after I'm filthy, I stay up until I'm exhausted, sometimes eat only when my Sim can't do anything else, work hard till I'm completely stressed etc. My Sims jump from extreme to extreme in order to succeed. So I don't want negative moodlets to overflow as well.
Also, I usually can use that free trait slot for something better or more fun - klepto, natural cook, neat, handy, etc. Something that has a definite physical effect on your Sim.