when we have change with a stranger. it seem like we make a new family and first impression is very important for everybody
say Hello is very important because it make your friend know you need to talk with them you should introduce yourself and change your attention for example activity,family, character and hobby. smile is a good way to show your impression because when you show your smile it mean you want to talk with your friend and they will come to know you then a culture of your roommate is important to you should educate & avoid yourself to do something because everyone have different culture, some like or accept you and dislike or except you . character is important same other one . you should've do a bad guys . you must to make a new character to move good and good and adapt your to friend character .
so,impression can discuss each people how they characteristic? it's a wat to make a relationship in the future