In this (yoga path) there is but one factor – resoluteness of intelligence. Comprehensions of the un-resolute are multi-branched and endless.
In the beginning itself, Krishna makes it clear that Karma- yoga does not consist in performing work ceaselessly, which, however, everyone does irresistibly. It truly consists in adopting the yogic attitude and refinement, which is a qualitative inner enrichment to our mind and intelligence. Transforming karma into Karma-yoga is truly an embellishment the intelligence has to gain, by dint of introspection and evaluation.
Karma-yoga thus consists in making the intelligence more and more enlightened and equanimous alike.
In the matter of being active and vibrant, none has any option at all, as Nature forces us to be active, by its sattva-rajas-tamo-guṇas. What is to be done is, while doing activities, the mind and intelligence should resolutely remain focussed on the Self.
If this is not ensured, the mind and intelligence will become multi-directional, paving the way for distraction, dismay and destruction.