its just in your head that way
not in my head 

 what does selfishness mean?
do you know that i work in many open source project and there is a piece of the cake for everyone and when the cake is empty or dry you just have to look for a new cake

is it that difficult? 

 me me me me me

you are the one who is selfish 

 If you wish to sacrifice yourself for the benefit of others, libertarianism is no barrier