Until I was 42 I had no experience of physical pain and little empathy or understanding for sick people, weak people, people in pain who couldn't pull their weight. I just swept them aside and motored on.
Then I got a herniated disc. The pain was excruciating and all consuming. I couldn't eat or sleep. After two months I ended up on morphine and already slight, I lost 10 kilos. Suddenly I was one of those sick, weak people.
I can't say I am thankful for the experience, but it was life-changing for me.
Grateful for the experience may be one thing but more importantly is the acceptance of what was discovered and how to use the knowledge after. I remember hearing that there were two general kinds of people after the holocaust camps, survivors and victims. There was a profound difference in life outlook depending on how each saw themselves. I don't think any were thankful for the experience however.