"The arrow that flies by day..." (Psalm 91:5)
One of the so-called Seven Deadly Sins is acedia (a-said-ia), said to be a state of apathy, boredom and dissatisfaction with one's lot. Early Christian monks referred to acedia as "the arrow that flies by day" because the temptation often struck in the afternoon, when hunger and fatigue made them susceptible to restlessness. It drove them out of their rooms to wander aimlessly, to seek better companions or conditions, rather than enjoy God in the "sweetness of their cells."
One fourth century Christian, Evagrius, wrote that when acedia "has taken possession of some unhappy soul, it produces dislike of the place, disgust with the cell, and disdain and contempt of the brethren who dwell with him or at a little distance, as if they were careless or unspiritual... He often groans because he can do no good while he stays there, and complains and sighs because he can bear no spiritual fruit so long as he is joined to that society; and he complains that he is cut off from spiritual gain, and is of no use in the place, as if he were one who, though he could govern others and be useful to a great number of people, yet was edifying none, nor profiting anyone by his teaching and doctrine. He cries up distant monasteries and those which are a long way off, and describes such places as more profitable and better suited for salvation; and besides this he paints the intercourse with the brethren there as sweet and full of spiritual life."
Can it be that our restlessness and desire for change (read here "a greater challenge"), is nothing more than ancient acedia in another guise?
The word, "acedia" is not a biblical word, of course, and, as such, is not proscribed. Some, therefore, may doubt that it falls into the category of sin or temptation to sin. But it occurs to me that my boredom and dissatisfaction could be nothing less than the sin of covetousness: a craving for something other than God has given me. 
Boredom and restlessness are endemic in me; I'm a rolling stone. But I must see my impatience for what it is and do what is required of me this day simply because God has called me to be faithful to his will. I must do it in the situation in which he has placed me, not yielding to my restless passion for that elusive "something more." I must tend "the lamp quietly for God without wondering how much longer it has got to go on.
It may be that someday God will move me to another place to serve His purposes there. In the meantime I must be calm, patient, willing to do anything, willing to do nothing--to sit and wait, to enjoy God in the "sweetness of my cell." Here in this place I must stay. Here I must be content with my Lord alone, until he guides me to some other place--on earth, or in heaven. "In this the long unrest is soothed and stilled; / Our hearts are filled!"
 The Institutions
 Cf., 1 Corinthians10:1-14 and Numbers 11:4-9
 From The Fruits of the Spirit by Evelyn Underhill