Worship vs. Performance

When you have a musical group or musician at church that is particularly pleasing to hear or has a particular mastery of music, at what point is it worship or performance?

For the individual musician:
It depends on their purpose or motivation. If a musician is motivated by pride or a desire to obtain glory or worship for himself, then it is performance and not worship Nevertheless, God can still use it to encourage others in worship.

For a musical group:
Some may be motivated to worship God. Others may be motivated to obtain glory for themselves. Either way, God may still use their efforts to bring glory to himself.

For the listeners:
A listener may seek to worship God no matter what music is playing. Music may encourage a listner toward a particular mood of worship.

Judging music:
All listeners have preferences towards different styles and they will judge a style according their preferences and maturity. Those who lack maturity will judge musical styles they do not prefer negatively. If one believes that only "traditional" music is appropriate to worshipping God, then they will disdain contemporary music as vulgar, base or irreverent. Others may view "traditional" music as simply dead. A mature Christian will recognize that one's heart is what is important in worship and that the style of music has nothing to do with it.