Rest assured that there’s motive behind everything. Look at yourself: Whenever you do something, you do it because you expect a result.
Some results are uncertain, but promised. You don’t know they’ll happen, but you’ve been promised they will. A promise of reward is perhaps the most powerful motivation. It’s partly why advertising is so successful.
Consider everything you own and why you own it. Consider everything you experience and why you experience it. Consider everything you’re told and why you’re told it. Consider everything you believe and why you believe it.
Every action is selfish, and in a sense, everything is selfish.