Very Energized won't harm your Sim. However, a lot of happy moodlets stacked up can be harmful if the Sim's emotion changes from energized to embarrassed, playful, or angry. I had a very flirty Sim tell two jokes on a date, separated by other socialization, and he went from very flirty to hysterical and died. So, anytime, you have a "very" emotional state, you have to be careful that the Sim does not become too playful or angry or does not get embarrassed (mortified). I think the Child's Play lot trait can give a Playful moodlet, yes? If so, that's a dangerous set-up.