The only thing that matters is love. Gravitate to the work, people, and causes you love, and give them your all. Follow this (and barring health or other disasters) you will be happy.So long as one loves what is true and that one's love is authentic, I cannot disagree with her.
When I addressed the graduating class of Blackburn College in May of 2010, I addressed the same question, but answered with Jesus Christ:
If you, dear graduates, seek to cultivate in the field of your souls the theological virtues of faith, hope and love, you will always be near to the happy life. These three virtues, infused in us by God alone, if we use them well, will always keep us on the path that leads to Jesus Christ, to him who is the happy life [more].