When Jesus said to the fishermen, "Follow me.", they did not say "That sounds like an interesting idea. Let me get back to you." If they had, they would have never become disciples of Jesus.
Jesus demands a decision; follow me or remain where you are.
Decisions lead to action; the immediate response of Andrew and Peter was to drop their nets and follow. (Matt. 4;19-20)
Commitment involves sacrifice. What the fishermen did might have been viewed as crazy to others. Leave a thriving fishing business to do what? Follow this man, the carpenter’s son?
I might have to lay down my wants and needs in order to take on a commitment of greater service. Even the things I might choose to better myself-- healthier diet, exercise-- involves a commitment that has to be followed up by the decision to do this and action to pull it off. Otherwise my thoughts might look like this: I could go on a diet and start exercising-- hey that's an interesting idea.
Following Christ takes courage. We need to know that the life of a Christian is not a guaranteed bed of roses. And if it was, remember, roses have wicked thorns.
Commitment to following Christ always demands two things; Decision and Action. Without those, it's just an interesting idea.