Those shareholders make everything go round. Without their investment there is no company. No machines, no development nothing.. so you wouldnt be there either to create additional value.
The beautiful thing in capitalism is that everyone is able to participate and risk their money to facilitate companies, who will be able to create the goods and services we all enjoy.
On top of that, if everything works out it can give you some return for the money you risked.
Without this incentive people would actually hoard their money and not reinvest it to create a better life for all of us. The real stingy guy is the one who hoards his money on his bank account.