We go through life talking to lots of people, and sometimes we think very little about who we are actually speaking with — this is especially important if we don’t think this person is influential.
It might be true that this individual is not, currently, very influential. They might not have very much to contribute to your discussion, or perhaps you do not see eye-to-eye and you have little interest supporting that person, or persuading them over to your side.
You might brush this person away and forget about them. But will they forget you? And what happens, in a few years time, when that person grows, their situation changes. What happens when that person, suddenly, gains seniority, power, and influence?
Think, who are you speaking to — who could you be speaking to?