Why does motivation last when you choose it, not when you are paid for it?
The motivation that lasts is not bought - it grows when an activity is yours, you are getting better at it, and it connects you to people.
Self-determination theory says durable motivation rests on three needs: autonomy (the choice feels yours), competence (you feel yourself improving), and relatedness (it ties you to others). Outside pressure and controlling rewards can feed the activity for a while but tend to crowd out the inner drive.
A kid who loves drawing gets paid 20,000 VND per picture for a month. When the money stops, she draws less than before - the cash quietly replaced the joy.
To keep yourself or someone else going, protect choice, show visible progress, and link the effort to people - not just a payout.
Whether it is studying, the gym, or a team at work, design for the three needs and the drive sticks long after the bonus or the nagging is gone.
ACR keeps you going: Autonomy, Competence, Relatedness - mine, getting good, with my people.
Learn the idea and practice English at the same time.