Q.
Can good manners and politeness affect your success in life? How?
A.
Definitely, yes! Most of our chances or luck is = are derived from the people in our surrounding environment.
We don't know which person gives opportunity to us = us the opportunity..
So, we always have to show good manners for other person= to other people, who can be the ones offering opportunities.

Also, we often meet a lot of people in our daily lives. If we are polite for other person everytime we encouter to other people every time we encounter them, it eventually makes us more positive. Thinking positively is significantly related to success.