The book HaYom Yom, from Day to Day, has daily sayings by the 6th chassidic leader, or rebbe (aka grand rabbi) of the Lubavitcher hassidim, as organized by the 7th rebbe.

Here's the entry for 6 Adar I, 5765 - February 15, 2005...

From my father's Sichot (talks):

"It is a magnificent gift of G-d to merit an innate sense - "feel" for doing kindness to another, to derive deep pleasure from it.

This can develop to the point that one cherishes the other more than one self. He may find many explanations as to why he deserves his own tribulations, G-d forbid, but to do so with regard to another's suffering - is absolutely impossible.