Helping others includes the gamut from those who feel it is your obligation, those who take advantage, those who take it for granted and to those who do appreciate your generosity. Regardless, what happens when you say no? Some may be surprised and resentful while forgetting numerous times when you had their back. Immunity to this is non-existent and it happens at work as well. So, next time you help someone, ask yourself why would you do it and if it is worth your trouble.