I was at my alma mater a few weeks ago, visiting some friends. On Sunday I ended up running into a lot of people I knew from college, and most of them knew that I had been in Mexico for a few years. But it seemed that most didn't know I was back in the States permanently. [I actually ran into the converse of this when I was preparing to leave Mexico. I told my friends there I was going back to the US and they thought it was just a trip or vacation.] Perhaps I was a bit sensitive, and definitely people were busy trying to get to where they needed to be on Sunday morning, but I have noticed that we feel uncomfortable around people who have done long-term missions work. I think that most people don't know how to interact with them.
This is unfortunate. Probably most of us don't have corresponding experiences to be able to really understand what it's like to live cross-culturally and all the highs and lows that come from that. I think that a lot of Christians have a skewed view of missionaries - that they have a particular calling on their life, are more spiritual, trust God more, they know what their life purpose is. This isn't necessarily true.
I definitely was a "missionary" for two years in Mexico; I went with a Missions organization, I raised support, the organization engaged in specific Christian evangelistic work. Honestly, though, I moved to Mexico because I wanted to live in a Christian community, because I wanted cross-cultural experience, because I wanted to learn Spanish, because I didn't want to jump into the rat race, because I wanted to learn to trust God. I didn't feel a call, I didn't experience a burning need to tell people about Jesus. Honestly, I never wanted to be a "missionary." I think that a better definition of my time was simply that I was living in Mexico.
So from my experience, missionaries who are back visiting in the US experience awkward situations. Others know that they have this different life experience that they may or may not identify with. But a big aspect of it is, I think, that for the most part missionaries rely on the donations of others. Raising support was one of my biggest challenges while in Mexico. I don't like asking for money; I felt uncomfortable when someone said they wanted to support me but then nothing came of that; it was difficult feeling like support only came a few specific people; I imagined that others saw me as being nice or writing update letters just to let them know that I needed money.
Yet, I learned to be more generous with my own money as people were generous towards me. I tried to trust God for providing for me through other people. I wanted to be faithful with the work that I was doing and a good steward of my resources.
It is hard to keep up with all the acquaintances we have in life, if they're in another country or moving to a new location. And I'm sure people feel odd when they know someone who is either directly or indirectly asking for money or support. I wish that we didn't have to feel that though. Living cross-culturally can be stressful, including returning to your native country. Raising support can be a constant struggle.
One other thought about missionaries is update letters. We were required to send out update letters at least quarterly, and I receive some weekly updates from missionary friends. I struggled with writing a good update letter for a wide audience that accurately portrayed my life and experiences. I didn't want to feign joy (with all of those exclamation points!) or seem disproportionally depressed, (even if I was struggling with things). How to honestly express my experiences? I think that this another area that is difficult for missionaries, to give such frequent reports or updates of their life.
So people become missionaries for a lot of different reasons and there are many different philosophies of what a missionary can or should do. But from my experience, they really are regular folk trying to straddle two cultures, with a lot of demands or expectations placed on them. My guess is that they feel as awkward as you do when you see them there on Sunday morning.