You will expose yourself too much. Don't expect too much and you won't ever be let down too much. Of course, in some sense this is true. If we expect nothing, we protect ourselves from disappointment. And how often we are disappointed with the world.
Politicians make promises.
The commercial market makes promises but often doesn't deliver. Self-help books make promises. Expectation invested in the wrong commodity truly is the mother of regret. But whether our expectations be great or miniscule, expecting the face of God or a face that defies aging, at the bottom of our expectations resides a great longing. Both the Israelites and the early Christians had great expectations because they had faith enough to have great longing.