Effort:

>Effort should be understood as including physical and mental effort, as well as investment of all types of resources. Generally, the more effort we invest in something, the more significant it becomes and the more intense is the emotion surrounding it. As the saying goes: the more you pay, the more it is worth. The converse is, of course, also true: when the stakes are greater, we invest more effort. 

Effort is closely related to the variables which signify the impact of the event, especially that of relevance. Thus, we invest more effort in something that is relevant and hence significant to us; conversely, something we invest more effort in becomes more relevant and significant. The saying “easy come, easy goes” expresses situations in which something we have gained without much invested effort is less significant to us and hence we may lose it quite equably.<

The Subtlety of Emotions, Aaron Ben-Ze'ev, 2001