The conclusion my wandering mind eventually came up with is that I am serving because inertia is a property of matter. That is Newton's First Law of Motion. It means that an object in motion will stay in motion and an object at rest will stay at rest until/unless acted upon by an outside force. I learned that lesson years ago from the theme song of Bill Nye the Science Guy. Guess what? We aren't above that simple law. People are made of matter too! But it applies to humans in a totally different way as well.
Entropy and inertia are the norm. That means that unless there is someone or something to start the ball rolling, the ball will tend to never roll. Because change is difficult to accept and implement, people will tend to avoid it even if the change would lead to a better and happier life in the long run. So that is what my job will be while I'm on my mission. I will work and serve and love and teach the people I meet on my mission with every last particle in me so that I can help be the "outside force" that they need to realize that a better life is attainable.
That is why I am leaving on this mission... that that I can become the "outside force" because inertia is a property of matter. I feel much like Ammon and what he said in Alma 26:12. He said:
Yea, I know that I am nothing; as to my strength I am weak; therefore I will not boast of myself, but I will boast of my God, for in his strength I can do all things; yea, behold , many mighty miracles we have wrought in this land, for which we will praise his name forever.
I, too, feel like I am nothing and I am definitely weak. But I know that the Lord is good and that He can heal broken hearts. He loves us so much and if I can even share that love with one person and make them overcome the inertia of the world that holds them back from progressing, 18 months will be worthwhile to me.