Since ages man has been struggling mainly with two states if his mind. One is the anxiety and the other one is the boredom. These two emotional states make him feel stressed at number of times.

These two states can be understood in terms of resources vs challenges.

When people think that their perceived challenges are bigger than the perceived resources, they are in anxiety.
And while they find that their perceived resources are bigger than their challenges, they experience boredom. In both the situations, they are in stress. This leads to their unwanted behaviors and habits.