Acting involves deciding to express an emotion, reacting means responding to changes in your emotions. Acting to emotions is fine, reacting is dangerous.
Reacting to both positive (happy) and negative(anger) are dangerous. It is easy to see the consequences of angry reactions- spoilt relationships, hurting people, rash decisions etc. Reactions to positive emotions are equally dangerous – people take on more risk for example. A more subtle such occurrence happened at a coffee meeting – as I got comfortable with the person – I opened up more. I was happy the meeting was going great, got excited & lost my composure. I shared more about myself than I should have, which then became a detriment to our relationship. I was jumping with joy but the carpet was removed below my legs!
Keep watching – the emotional reactions are dangerous!