Torn

I just don't understand how it is possible to want two opposing things at the one time. OK, I do understand, but I don't get how I let it get to that point. 

If one can never have the whole pie, then how do I decide which cuts of it are negotiable, and which are not? What happens when no cut is not wholly bad, nor wholly good? What if none of them are so simply mutually exclusive?

Is being realistic and settling the same thing?