From some economics class I took in college, you can define 4 types of expenditures based on who pays the expenditure and on whom the money is spent. The possibilities are:
1) I pay the expenditure and the money is spent on me.
2) I pay the expenditure and the money is spent on someone else.
3) Someone else pays the expenditure and the money is spent on me.
4) Someone else pays the expenditure and the money is spent on still another person
Type 1 is most personal spending. I have an incentive to be frugal with the money yet I still buy things that I like.
Type 2 is, for example, when I buy a gift for someone. I have an incentive to be frugal with my money but I may not know the gift receiver's tastes and preferences well. So I may or may not buy them something that they would like to have.
Type 3 is like when I go to a business dinner and someone else is paying. I have no incentive to be frugal with the money but I'll buy something that I like. (Personally I usually order the filet mignon).
Type 4 characterizes a lot of government spending. It's not their money they are spending so there is no incentive to be frugal with the money. And secondly, the money is spent on someone else and the government probably doesn't know the tastes and preferences of those upon whom the money is being spent.
In general, I know what I want better than the government knows what I want. Could we change type 4 spending to another type? Yes, in some cases. Look at public housing. Instead of having federal government build rundown, poorly maintained apartment complexes when could just give the people that qualify some money to spend on their housing or how ever they see fit. But the feds think they know better what's good for us. We can't allow someone to choose what they could spend money on.
Want to read more. Check out the book "Free to Choose".
http://en.wikipedia.org/wiki/Free_to_choose