Getting thanks is a bit like getting compliments. You graciously accept them all, even if some of them seem a bit automatic or even empty. (Don't look a thankful gift horse in the mouth - or something like that.) They are also like compliments in that it is typically not appropriate to demand them, even when they are deserved. But it can create some interesting tensions. If, for example, you gave someone a gift and didn't get acknowledgement of it's receipt*, it can be difficult. You may contact them trying to make sure they are okay, you may have conversations with them, you may even make sure that the gift was received - worried perhaps that it had gone astray. Now, Miss Manners says, after a few gifts, someone who continuously fails to acknowledge your gifts, may be removed from your gift giving list. (She also points out that there are some people in your life, that however right you may be, that for whom such a decision may cause more trouble than being right is worth and to consider that.)
But what are the legitimate - if not entirely excusable reasons - someone might not give thanks?
Well, as referenced above, they may have forgotten.
If it was an event that garnered a lot of gifts, there may have been some confusion over who was the gift giver. (Yes, there are steps to prevent this, but sometimes those detailed lists get lost.)
They may be trying to figure out how to properly thank you.
They may think they have thanked you. (One poor woman on "Oprah" had carefully written out thanks for every one of the wedding gifts and then gave her new husband the job of taking them to the post office. Two years later, they were cleaning out the garage and found the box of thank you cards - all addressed - just sitting there. Hubbie had put the box down for a second, got distracted and never got un-distracted.)
They may know full well they need to thank you but circumstances have taken up their time unexpectedly.
So, as we head into a season of thanking and thankfulness - may I suggest, say thank you to lots people, say it sincerely, and while you are giving thanks, give yourself an extra one (or two) for any that might have gotten missed.
*Note: I promise, promise, promise that this is not a veiled attempt to wring thanks out of someone. The holiday made me start thinking about thanks, and this is where my mind started to go.