Ephesians 5:17 (NKJV)
Have you ever been in the situation where you were going out to eat with some friends or maybe traveling to some place and there was a difference of opinion? Maybe there were different ideas about what restaurant to go to, or it could have been that you were traveling somewhere and there was more than one route that could be used to get there. It might also be true that someone knows something about a restaurant or route that would make their idea the best. But if you ever want to eat or arrive at your destination a decision has to be made where someone's idea is accepted and someone's idea is rejected.
Everyone has ideas and a will of their own, but if we are wise, we will always find out what the best thing to do is in every situation. For Christians, our goal should be to find and follow the will of God. But this often means that for us to follow the will of God we have to put what we want, our will, to the side. As it tells us in Ephesians 5:17, we need to be wise and understand the will of the Lord. This would mean more than just having the knowledge of what God's will is. If it is wise to know the will of the Lord then we should pursue the will of God in our life.
In 2 Peter 2:10 it talks about people who live their life according to their natural desires, the flesh, saying that those people are "self-willed". Paul told Titus that one of the requirements for an overseer was that they could not be self-willed (Titus 1:7). In both of these cases it is talking about people following their own will, not the will of God. For us to do the will of God we must submit our will to God's will and allow His plan to be our plan. God's will and plan for our life will always be the best thing for us, but we must allow His will to win over our will. That is the true path to happiness and success in life.