there are two motivations AFAIK:

• big pile of cash
• boss barging into one's cubicle and yelling at one to get one's butt in gear and get it finished, otherwise no big pile of cash at end of project

oops! that means there's only one motivation, according to the "monism" theory of animation
as opposed to the "dualism" theory of animation, in which the motivation is either a big pile of cash, or because it's so fun and easy and only takes a few minutes :lol:

p.s. in response to the following msg, I don't actually recall reading anything (poser manual, carrara manual, photoshop manual), but mostly learned by watching videos.  however, reading things is how humans have learnt things over the last 3 millennia - can't be bad.