The quality of your life and character isn’t determined by circumstances external to you—the things that happen to you. Both are determined by the internal choices and decisions you make in light of them.

Which is good news because you can actually do something about them.

“It is not as important to change our circumstances,” Tim Keller says, “as it is to change our heart’s attitude and stance toward them.”

Your attitude is the key to turning even the worst situation around. How you think drives everything else.

It’s easy to have a positive attitude when things are going well. But it’s a different story when they’re not. Those are the moments you need encouragement from a good friend. I want to be that good friend for you today, and remind you of a few things.

Every situation (good or bad) has the potential to shape and impact you for the better. It might be hard and nearly impossible to get through, but it can make you tougher, stronger, and better if you’ll let it. The mental game is always the hardest part of any battle. Staying positive and upbeat when the waves are crashing about you is perhaps the most difficult thing you face on a regular basis.

When things aren’t going well, I want you to remember what good things it could mean for you. Opportunities to grow and learn. Opportunities to be a better version of yourself today than you were yesterday. Opportunities that remind you why you’re here in the first place.

Check your thoughts the next time you find yourself in the damp dark pit of self-pity. Remind yourself that you’ve still got gas in the tank and some fight left in you. You’re not that easy to beat. You will never quit. You’re tough enough to hang in there and find the silver lining to even the darkest cloud. A silver lining that keeps you pushing forward and driving on when things are at their lowest.