Every impovement is a change

"Not every change is an improvement, but every improvement is a change."
(c) Eliezer Yudkowsky

Every change brings uncertainty. Bigger changes bring greater uncertainties. Uncertainty comes with the feeling of discomfort. We fear to lose the comfort in our miserable, but predictable lives. This fear stops us from going forward and making great improvements in our life.

If you want have more, you must first accept the fact, that you're going to lose what you already have. Be ready to sacrifice, there is no other way to achieve great goals.