Service versus sacrifice

How do you draw the line? Is it necessarily bad to sacrifice, or just unhealthy to put yourself in the habit and mindset of doing so to the detriment of your own well-being? What if they come bundled together, and you can't be of service without a little sacrifice? Is it no longer a sacrifice if you make a willing choice, in order to do service that pleases you? Is the distinction between service and sacrifice entirely in the mind, that is - if you feel good and fulfilled afterwards it was service, if you feel cranky and lessened (psychologically, emotionally, financially) it was sacrifice? Or is there some intrinsic measure that can be applied to the act itself? Is sacrifice merely service that became boring, or overstayed its welcome?