Cant count the number of times Captains and I have pushed wheelchairs, helped find lost items and escorted passengers. It isn't part of the job, but it is appreciated. Usually the wheel chairs are the generation of people who still remember the "romance" of flying and who are generous in their praise when they have "a Captain" to help them out. They believe we are the best and it is a pleasure to make that little corner of Disney World a reality.
Doing nice things for folks is more reward than work.
Besides, Flight Attendants are stuck until the passengers are off the airplane. If a W/C passenger is not getting picked up it can make their day difficult.