It's all about Jesus
This is a very simple statement, yet absolutely critical. If we loose sight of the centrality of Christ in all we do, all we are, all we seek to become. The we have stopped being Christians and have become merely religious! The one we serve must always be more important than all our activities of service; the one we worship more important than the mechanics of praise; the one we minister on behalf of more important than "my" ministry; the one we witness to more important than the numbers of people we reach; the one who gives us authority more important than "our" results in prayer; the one we preach about more important than how well we preach. His glory is more important than my honour. I would rather be wronged than vindicate myself in a way that brings dishonour to the name of Jesus.
This was the difference between Mary and Martha. Martha was caught up in the activities, but Mary was first and foremost caught up with Jesus.
This does not mean that service is not important! Oh, how this passage has been abused to that end! We are first and foremost servants, before we are anything else (with the exception of worshipers). And it is as servants that we will be judged, and commended or rebuked. God has little good to say for the "wicked and lazy" servants who think they can cruise into glory without putting what God has given them to work (Mt 25:26). Our service is important, but it must always be for him. How sad, that on the day of judgement, there will be those who have worked all their lives under the impression they were pleasing God, yet Jesus will say to them: "I never knew you." (Mt 7:23) God takes no pleasure in religious acts, but he delights in lives surrendered to his son. One day, every knee will bow; we are God's prophetic people to the extent that we bow the knee to Jesus alone today.
And he made known to us the mystery of his will according to his good pleasure, which he purposed in Christ, to be put into effect when the times will have reached their fulfilment--to bring all things in heaven and on earth together under one head, even Christ. (Eph 1:9-10)