everything you need to know you learned in kindergarten

This concept is something that I saw in posters while going to school all the time but I am sure it has some validity.  Unfortunately I feel like I never really learned how to share.  I know this may sound odd to some of you while I am sure it seems like I am very generous and do take the time to consider many people in my life but sometimes I make this realization and I can't help that I'm a little greedy.  When I get something new I don't like others to use it.  I want it all to myself because I paid for it, I earned it, and it's mine.  How child like is that?  I can't help it though, I feel as it is something I can't change at this age but I just try to hide it.  So I guess this is just a warning, if I have something new, I don't want to share it, don't ask because I am probably too nice to say but I'll be secretly bitter at you.