Inner peace is not apathy
It's very important not to confuse serenity and apathy. One of the characteristics of a stable spiritual practice is not to be vulnerable to outer circumstances, whether favorable or unfavorable. The practitioner's mind is likened to a mountain that the winds can't shake; he's neither tormented by the difficulties he may come across nor elated by his successes. But that inner equanimity is neither apathy nor indifference. It's accompanied by inner jubilation, and by an openness of mind expressed as unfailing altruism.