Our happiness depends on factors intrinsic and extrinsic. Sometimes our mood affects our behavior and sometimes what happens around us affects our mood.
In either case mood is a temporary state of mind. The tricky part is when our mood stays with us for a long time and leads to irrational behavior. When we seek happiness and instant gratification and are unable to accept the outcomes that are not in our favor.
In a world where everyone is fighting for our attention, where we are bombarded with new and happening stuff, the tendency to remain in a situation of unhappiness remains strong.
Children need to to be explained that they cannot respond to every change or experience that they are exposed to. Some things are possible and many things are not.
Mood sits behind us and it is never the other way round.