John Calvin on emotions...
This rather interesting (but long) article on fatherhood and the church happens to cite John Calvin's comments on Acts 20:37:
When the Spirit…commends their tears…he is condemning the thoughtlessness of those who demand from believers an iron and inhuman firmness. For they falsely suppose that the feelings, which God has implanted in us as natural, proceed only from a defect. Accordingly the perfecting of believers does not depend on their casting off all feelings, but on their yielding to them and controlling them, only for proper reasons.
You can find the quote in context (and in more-antiquated English) here if you want to investigate further. I'm still trying to figure out how exactly to interpret Calvin's reference to "controlling them" in the context of the rest of the verse.