Mr Nice GuyˌMr ˈNice Guy British English, ‖ Mr. Nice Guy American English 
someone who is too nice and friendly, so that other people treat him unfairly to get what they want – used especially in the phrase ‘no more Mr Nice Guy’, to say that you are going to stop being nice and letting people treat you badly.
someone who is too nice and friendly, so that other people treat him unfairly to get what they want – used especially in the phrase ‘no more Mr Nice Guy’, to say that you are going to stop being nice and letting people treat you badly.