How many times feeling of selfishness has overpowered your self-conscience?

i want to ask you here how many times you chose rather to be mean?well it has happened with me mainly in case of you can say heart matters(personal as well as public) in which either my love was at stake or when i just had to get something out of my way ..in other incidences i would mention the envy thing or the arguments with any one whom i wanted to win over the other person..i opt for being selfish only when the persons i am dealing with act excessively selfish then even i do the same to teach them a lesson and to prevent being exploited or taken for granted...and i don't think its bad to become selfish to get your things back be it any living or nonliving thing,or in situations in which your ego is at verge of getting hurt..how many times this has happened with you?did you feel satisfied or developed some inner conflicts? for me most of the times it has been proved to be a good decision..