It happens to the best of us. With each passing day, our hearts get clouded with any number of things: envy over a coworker's cushy new account, bitterness from an argument with your spouse, feeling like a failure after a struggle with your child--the list is endless.
It's just like windows. They do their job, day after day, letting the light in and keeping the elements out. And every day, they get just a little dirtier: grease from the kitchen, funk from that steamy bathroom, cobwebs, pollen...
It takes a while, but eventually all that filth builds up until it's visible on the windows, and you have no choice but the clean it off. It's obscuring your view.
Same with us. All those daily struggles, all those feelings that we just don't want to process--they build up, until they've changed our attitude, our thoughts, our actions, into this dirty mess that really needs to be cleaned up.
Take a minute and think: do you have some grime in your heart that you just need to get rid of? Someone you need to forgive? An attitude you need to change? Think about what it would take to remove that issue from your life, and then do it.
You won't believe how you ever saw through that grimy window once it's clean again, and when it is, you'll have a fresh perspective to see the world.