Up on the Mormon Lingo?!

So, last night my brother Neil and his family were up in DC, so after work I met them at the temple to see the lights and see the Joseph Smith movie (which I love!). As a side note, i had to laugh because i was greeted by my 2 year old niece London screaming "Ah Weenda! (that is Aunt Melinda for all of you...) I have my panties on!), she's potty training, and now everyone in D.C. knows! :)
Anyways, At the end of the night we were outside taking pictures and I was taking one of the family when in the background we here a man's voice start singing "good night sisters, good night sisters” over the intercom. My sister-in-law Ali and I start laughing and she asks if he was singing to us as it was closing time. I said, "No to the sister missionaries, gotta love senior couples!" Simultaneously this couple asked me to take their picture and I said sure.
The man goes "what did you call them? Why cant the just be couples". I laughed and said I served my mission on Temple Square w/ a lot of senior couples and absolutely love them. He goes, I don’t want you to take my picture and comes and gets his camera (I thought it was because I served on Temple Square) so I laughed and said, “no I take good pictures honest, I've taken a lot!” He was so flustered and said ok but was still so angry. I took their picture and he just kept going on and on about being called senior couples. I said “that is what they like to be called”, he just couldn’t believe it! I asked if they were familiar w/ the church because obviously they were not members. So I just explained that retired couples serve missions like what you see the women inside doing, and lingo, we call them senior couples. He was then ok with the notion but still completely flustered... funny I never thought of it in a derogatory sense, hmm, as we don't call young missionaries couples, they could just be called "couples" but it just doesn’t have the same ring to it, sorry!!!:)