While he did a good thing on a whim, he didn't think much about it. His whole life was dedicated to such cause, he just thought that the driver was honest enough to receive his help.
People would often think kindness was when one help a person but his philosophy was different. People had to deserve their redemption or else they wouldn't appreciate it in the long run.
Just like the homeless problem that was intensifying around the world, many people think they have the solution for it like giving handout or other assistance but somewhere along the line, they wouldn't be able to sustain it as the people recieving help would think that they could just live their life expecting others to help them.
That's why Samuel abstain from helping in such circles even if there were plenty of people that needed help. He would much rather use his money to open orphanages that would support the next generation than to sink his money into the current one.