The raison why you dressed up is beacouse of a respect to the persons whom invited you.
One of the most difficult to chose what to wear for men
Are you get suit up according to your partner ?
What kind of invitation you are going ?
Are you going to a black tie event ?
Are you going to a wedding ? Are you part of the familly or only invited ?
Buisness celebrations , inaugurations you also need to be smart.!!1