New Delhi, Aug. 25 -- "Also, stick around. Don't lose your heart, just keep going, keep at it."

It is the kind of quote that sounds almost too simple at first. Stay. Don't give up. Keep moving.

But there is something more interesting in the way Mark Ruffalo puts it. He does not just say to keep going. He says, "Don't lose your heart". And that changes the meaning.

Anyone can force themselves through a difficult day. The harder thing, perhaps, is to go through disappointment, fear or anger without becoming numb to everything around you. To keep caring when it would be easier not to. That is what makes Ruffalo's words feel particularly relevant.

His own life has not followed the smooth, inevitable path people often imagine for a Hollywo...