Please give me a motivational speech for my workout by making me feel bad if I would skip it.
Motivational speeches are notoriously difficult to write, but here is something that might help you get through your workout:

I know skipping the gym can be tempting sometimes, especially when life gets busy or there's just no energy left in the morning. But what happens next time you find yourself feeling sluggish and unmotivated? Will you continue with this routine and make sure everything works out fine later on down the road? Or will you choose another day off instead of getting up early, wasting more precious hours at work or school, only to realize how much effort was wasted all together? 
If you're still going to skip the gym today then consider this: You could wake up one day 20 years from now realizing that you regret missing an opportunity like never before because you let some other days pass without even trying. 

Do you want to have such a big impact on someone's life tomorrow, as well as many others throughout their lives, or do you prefer doing nothing at all? 

The choice is yours.