Interesting subject ...there is a difference between extrinsic and intrinsic motivation . Speed could go either way ...either you are bored and slow down or loving the job and hence slowed down . Certain motivations are towards end-goal while others are towards having a process focus . This article goes into depths on these issues with simple expression ... https://faculty.chicagobooth.edu/ayelet.fishbach/research/SPCOTilleryFishbach.pdf
Compendium on Work, Health , Learning , Social and Spiritual Aspects of Leading a Complete Life