God's word says in Proverbs 3:5, "Trust in the Lord with all your heart, and do not lean on your own understanding."
Trusting God wholeheartedly involves actively not trusting in yourself--not trusting in your own comprehension, your own experience, your own perspective. The point is don't lean on your own limited and flawed understanding, lean on the perfect Lord.
The leaning described here isn't the shifting-your-weight-to-one-foot variety. It's talking about the kind of leaning in which you place all your weight on something or someone so that they are holding you up, supporting you.
Here's a simple test: you're truly leaning on something if you'd fall over if it wasn't there.
That's a picture of the kind of trust God wants us to have in him. Trusting in the Lord with all your heart involves leaning on him in such a way that you're completely dependent on him.
When we're leaning on God we're going to feel off-balance. Too often we want to trust God but still be independent. We want to trust while feeling in-control. We want to lean while standing on our own two feet. But that's not real trust is it?
Proverbs 3:5 teaches us that trusting God is living in the reality of not being in control. It's feeling dependent. It's feeling off-balance. It's feeling weak. These are all feelings that in our pride, we're prone to run from. And yet there's no better, no safer place to be than leaning on the everlasting arms of our loving Savior.
Next time a non-Christian friend accuses you of making God a crutch say, "Well, yes, I am leaning on the Lord completely. What are you leaning on?"
We're all leaning on something. If it's our own understanding, we're fools.