There are days when my alarm clock goes off (yes -- sometimes I do need the alarm to wake me up) and I don't feel like getting up.
I consider staying in bed and not getting up. It's not like anyone will know if I skip a day of work or don't hit the gym or don't write that blog post.
I always get up.
I was listening to a Tony Robbins audio program which is 3-4 hours long. Research shows that when someone hears information audibly, he only remembers 5-7% of what he hears. The only way to retain more of the information is to either physically experience it (which ties emotion to the information) or to listen to it over and over again (which beats the information into your brain).
Tony emphasized that the one thing people could take from his program, if they remembered nothing else, is controlling your ability to force yourself to take action, especially when you don't feel like it. That ability is 85% of the difference between an achiever and a lazy person who gets nothing done.
None of us always feels like it. Your favorite rapper/actor/football player does not always feel like going to work, and neither does the unknown rapper/actor/football player. In the end, the one who leaves their mark the strongest is the one who shows up, mentally and physically, even when they have every good reason not to.