If we are not karta (doer) for karma (action), then who is karta? Krishna replies (3.5) "No one can stay for even a moment without performing karmas as all are compelled by gunas (characters) born of prakriti (nature) to perform actions."
Three atomic particles, namely electron, proton and neutron form the entire physical world. Similarly, three gunas viz. Satva, Tamo and Rajo are responsible for driving us to perform actions. In that sense, they are the real karta.
Krishna further says (3.6) "The individuals who forcefully control the organs of action, but whose mind rotates around thoughts of sense objects is a hypocrite and deluding himself."
We are brought up and governed by a system of reward for good behaviour and punishment for bad behaviour, both at the familial and societal level. This results in a split personality with no coherence between our inner and outer selves.
For example, when someone hurts us, we may restrain ourselves in terms of words and actions, for the sake of good behaviour but the mind gets filled with hatred, regrets and a sense of injustice.
Krishna is never in favour of suppression or numbing which he calls mithya (delusion), but instead, advocates for attaining samatva (equanimity) where hurt and praise are treated as equal and hence dichotomy disappears.
At the core, nobody wants to live in this misery, but very few know how to come of it. That's why Krishna immediately gives a solution (3.8) to engage one's organs of action in karmayoga (yoga of action) without attachment.
The crux is 'without attachment'. It's performing karma without attachment to karta with the realisation that gunas are the real karta; performing karma without attachment to karma-phal (fruits of action). It's the detachment of senses (controller part) from the sense objects. Unconditional love emerges when attachment goes.
Source - Daily World