"...but it doesn't matter"

At what point does positive self talk become outright denial? The Book says that when you experience discomfort when running to acknowledge it, but then follow the negative thought with "but it doesn't matter." For example, "My right foot has fallen asleep in my shoe again but it doesn't matter." "My breathing is slow and laborious but it doesn't matter." "I have undertaken an unrealistic goal but it doesn't matter."

At what point does it matter? What is the difference between this mind-chatter and denial? I mean, can I go through life dismissing all of the discomfort and stress? I imagine I would be a happier, more optimistic person, but is that reality? Or maybe this is just part of creating my own reality. More to consider the "I am..." and turning the doubt into a positive. (Or if not a positive, at least neutralizing it.)

Speaking of which, I completed my first week of running and started the second. Even while in Florida I was able to run the plan. Running with company makes a difference but more about that another time. Total for the week was about fifteen miles. Not marathon length, but the most I've ever run. It's a first. From this point forward, it will be all about "firsts." This week will be my "first" run of six miles ever. It's exciting. I'm nervous about the increase but it doesn't matter. (Uh oh.)

I ran the required three miles today and I felt good. Strong. Capable. My legs were heavy at the beginning (but it doesn't matter) but loosened up as I kept going. Imagine that a month ago I was struggling to run the park loop. Tomorrow I will run it twice for my four mile day requirement. I will be light in my shoes, effortless as I move along the trail. I am a llama. I am a llama. Okay, at times I am not fully a llama (but it doesn't matter).