I love most of my life in this country. There are however a few nuances that are frustrating that get under everyone's skin that lives here - Thai and expat alike. Here is one that you are almost certainly going to encounter if you stay here for any amount of time really.
Thailand basically has a attitude of "Jai yen yen" which simply means "take it easy" or "relax"... This attitude unfortunately extends to many retail businesses where I dunno about you, but I normally don't want to wait just however long.
Term one: "Raw Sac-krew"
If you go somewhere and are ever told "raaw sac-krew" this means "just a moment"
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However, just like this all-too-often-present screen on my computers, "a moment" isn't necessarily a short thing. If you are told "raw sac-krew" do ahead and get your phone out. It is going to be minutes, perhaps many minutes.
Term two: "Pep Diaw!"
This term also means "just a moment / minute" but seems to indicate that the wait time is going to be significantly longer than the "Raw sac-krew" mentioned before.
A "pep diaw" indicates that you should get your phone out and perhaps find something to lean against while still making your presence known so they don't completely forget you are there.
Term 3: "Nang gone"
If you ever receive the dreaded "Nang gone" command you are likely in for a very long wait. "Nang gone" means, take a seat first and if this happens to you it is extremely likely you are going to be where you are for a very long time. You may wish to go ahead and fire up at least an episode of a TV show on Netflix.
Term 4: "Leum!"
If you ever hear this, you may as well leave the store you are in because "Leum!" means "I forgot about you!" in which case the thing you are inquiring about is probably either not possible or something the staff have no intention of trying to do for you.
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All in all, it is generally a good idea when relocating to Thailand to go ahead and forget everything you expect about efficiency in many environments. The rush rush! attitude of the West doesn't really exist over here and in many ways this is a good thing. I would imagine this lack of stress is a good reason why Thai people seem to have less worries, less stress, and less health issues that we are plagued with in the Western world. If you are a nervous person who is going to get upset any time things take longer than immediately I highly suggest you figure out a way of doing your shopping online, which is kind of what most people today do anyway.
This is kind of meant as satire but is based at least somewhat in reality and the words are real. I am in no way criticizing Thai people or trying to say their culture is wrong. I love it here and love the Thai people (except for the government)... in case that wasn't evident