'First impressions matter' means that the first image that one gives is a main factor that determines how the relationship will begin. I agree about this phrase because I myself sometimes experience it. When I meet a new person and his or her first impression is nice, I become more open minded to them and get close to each other quickly. Additionally, I tend to tolerate trivial mistakes or faults of him or her. Just having a good first impression makes me to justify and accept the problems more generously assuming it was not intentional and wouldn't happen again. However, if the first impression of new person is bad, I inclined to make a wall in my mind between him or her. I think most of people would have this kind of instinct because they developed by an experiences to avoid those who might be harmful. Anyway, this solid wall is hard to break that I apt to be more strict and cynical to everything that I undergo with him or her.

'First impressions matter' means that the first image that one gives is a main factor that determines how the relationship will begin.