The man was the chair of a small building company, it appears. His interlocutor was one of his employees, who seemed to have used some old silicon to fix something in their clients' house, and he was very upset about it:
"How many times do I have to tell you, you need to open a new can of silicon for a job like that! If you have old silicon that's been sitting in the van for over a week, you can always use it for small jobs, in subsidised housing or the like, but don't use it with important clients!"
Silicon tends to spoil when left open for too long, apparently. So, logically enough, you should then keep it for when you have something to fix in a lower-income family's place. You learn lots of things when you ride on the train. Not long after, the employee must have asked for a renegociation of his salary, because his boss's reaction was unequivocal:
"Wait a minute, Nick, you don't mean to earn more money than I do now, do you? Keep up the good work, and maybe you can have an extra fifty euros at the end of the year. That's good enough. Don't ask for more."
There were children on that train as well, squealing and singing mock songs about each other's body odours and insulting each other when they caused luggage to drop on the floor, and the man soon put an end to the conversation. A shame, though: I would have loved to eavesdrop some more and learn more valuable life lessons, and keep them in store in case I ever end up in subsidised housing and someone in the building is wondering why the repairs never seem to last a month.