I've noticed this in myself, there are low phases where I will literally search for inspiration in some form (books, music, people, films, anything really, tend to find it in the oddest places)Perhaps the only difference between the two (extrovert and introvert) to be observed is that the introvert can more easily adjust his ways because all that he requires for the adjustment is the will of his own contemplation, yet the Extrovert requires the external inspiration
It's looking for something outside you that articulates the struggle going on inside you
What are some of the things that have inspired you?