Sleep. Something many of us take for granted.
I had a few very sleepless nights recently. Nothing bad happened to cause me anxiety or anything, I just woke up in the middle of the night and lay awake for several hours, desperately tired, but not sleeping. The following days were long torture of fatigue.
It made me realize what it must be like to suffer from insomnia.
Last two nights I've dropped off to sleep again with no problem, and it made me appreciate what a blessing a good night's sleep is.