In my 46 years of traveling as an evangelistic speaker, I have discovered something that isn’t truly surprising, but it is instructive.

The believers who impact others the most are not those who respond with an “attitude of gratitude” when life is going well, but those who respond with sincere thankfulness when life is upside down.

As I write this, I just returned yesterday from a man in a senior-living facility who practically overnight lost strength in his legs and is now confined to a wheelchair. He made the comment, “I don’t like who I am, but I like where I am.” He then went on to explain that although he regrets not being able to walk and needs a nurse’s assistance from 9 to 9 every day, he is grateful for the facility he is in and the care he is receiving. I can assure you, that even as I had lunch with him and noticed how people responded to him, they were extremely impressed by his attitude in the midst of adversity.

Everyone knows how to handle life when everything goes right, but when others see us as believers responding with an attitude of thanks while going through life’s toughest trials, that’s when we can best communicate the person of Jesus Christ and how much He means to us. They soon discover how seriously we take the admonition in I Thessalonians 5:18: “In everything give thanks; for this is the will of God in Christ Jesus for you.”

No one has exemplified this to me better than my mentor Dr. Haddon Robinson. In my book A Mentor’s Wisdom: Lessons I learned from Haddon Robinson, my twelfth lesson deals with when he said to me, “This Parkinson’s is rough. But the people are great, and the food is good.”

Not long after I received my Doctor of Ministry degree through Dr. Robinson in 2009, I found out he had been diagnosed with Parkinson’s Plus disease. I was heartbroken. He told me the doctors had informed him that it would take its toll in about five years. He actually lived a bit longer than that and went to be with the Lord on July 22, 2017.

What struck me the most was that he had no complaints. He did not question God’s ways, had no bitterness, and no anger. When I later went to see him in a Parkinson’s facility in Lancaster Pennsylvania, I knew it would not be easy. I never thought I’d be pushing my mentor’s wheelchair down the hall.

When he spoke of how difficult the Parkinson’s disease was, I could see the strain on his face. But then just as quickly, it was as though he did not want to linger on that thought. He told me how kind those helping him were and how grateful he was for the food. He also asked how I was doing and what was happening at EvanTell.

I have never recovered from that visit and hope I never do. Dr. Robinson was convinced God was using that experience to conform him into the image of God’s Son. Here was a man who was voted as one of the top ten best preachers of New England who, overnight, had to cancel all of his speaking engagements. I am certain I asked, “Why God?” more often than he ever did. In fact, his daughter told me that one time when she asked him, “Don’t you ever get mad at God?” he responded with, “Oh no, Vicki. I could never get mad at God.”

Related: Sharing Your Faith During a Thanksgiving Prayer

But that’s my point. I know for a fact he had such an impact upon non-Christians he came across because of his attitude of thanks when Life had hit him like a bombshell. When he spoke about the Savior, people listened. And when he spoke of a deep faith in a good God, they knew he meant every word of it.

How often have we lost our best opportunities to witness when life turns upside down? That attitude of thanks we convey can go such a long way in impacting people and letting them know through our own testimony that His grace is sufficient.

As Thanksgiving approaches, may I ask you the same question I have to ask myself? Are people struck with your attitude of thanks—not merely when life is a straight and easy road, but when all of a sudden it takes a nasty curve?