Intentions?

Must every actions that we do have intentions or just mainly dependent on our wants? Is it possible for us to just do something just for the sake of helping others without hoping for rewards in the short run and also in the long run? I had these thoughts in mind but a friend of mine told me that maybe I was thinking too much and was being paranoid. He said that most probably, others weren't treating me nice hoping for a reward or anything beyond a friendship. At first, he sounded reasonable but still, I do not agree with him entirely because I believe that there should be a purpose in anything at all. He did managed to made me think that I was wrong back then because the issues that I had in mind were only entirely based on my intuition and feelings. As time passes, others begin to ask me if there was something going on and I turned out speechless knowing that my initial gut wasn't all that wrong after all. My solely based instincts somehow begin to make much more sense to me than they have ever been before. I want to believe that I was wrong and kept on insuring myself that there are still possibilities that I am not all that right because I do not have a solid prove or justification. Honestly, I want to believe it but then, it was not the first that I have came across this sort of thing and there should be a reason for me feeling that way. Feelings won't come uneasy if it's the right person doing the right thing at the right time. As for me,everything felt so out of placed and it doesn't seem right at all.