There is a kind of service, which one may think is for the Lord, that is done resentfully.  The service is rendered, but loathed in the process.  The ones served do not sense love nor concern with this attitude.  It does not draw them to the Lord.  There are certainly times that we serve out of doing what needs to be done, but even that can be done with a good disposition.  We should serve out of faithful love and in gratitude for all God has done for us.

“Render service with enthusiasm, as to the Lord and not to men and women” Ephesians 6:7 (NRSV).