Fashion for a certain leader as a factor to influence electoral preferences

During elections, it often happens that the electorate goes to vote for one candidate with more enthusiasm than another. Why is this happening? Why does one candidate like more than the other, even if both are very similar to each other?] Why can a man who is already known to the people not win his best deeds win? 2 How can it happen that a person not related to politics suddenly becomes political leader and election winner?