=== Being not so impressed with your talents that you end up using the the song merely as a vehicle for a display of ones vocal and instrumental expertise."===

I see what CS means by this, & why Brian quotes it approvingly. But surely every performance one gives of anything should be to the best of one's ability which surely = using such 'expertise' as one has. The word 'merely' is a bit tendentious here, I can't help thinking; as if there were something dishonourable in being as expressive as one can & that someone who puts real effort into performing is somehow acting against the true interests of the song. I don't want to push this point too far or seem as if I am totally disagreeing with the attitudes expressed; perhaps I just mean that there might be a tendency to lean too far in the other direction against putting anything 'personal' into one's rendition.