What is harder, running six miles in 60 minutes or doing yoga for 60 minutes? It all depends on the person. When I said thank you to my yoga instructor after a 60 minute class she seemed surprised. As I left, I again looked her in the eye and thanked her. I told her I could run all day, but her class completely exhausted me. She had a hard time believing it.
Being thankful is a spiritual discipline and what seems so easy for one person, may be extremely difficult for another. Being thankful may be hard for you, and even intimidating to do. I was blessed to have a mother, who made it one of our families core values and after years of saying thank you, it is fairly easy to be thankful. If you are new to the discipline of being thankful, don't compare yourself to someone who has spent a lifetime of being thankful. Just start somewhere, and practice on someone every day. Being new to yoga and the only male in the yoga class is fairly intimidating, and if I just keep practicing, one day, I will be fairly decent at it. For now, I just do what I can do, and be encouraged to start somewhere in the journey of being a thankful person.