Mysterious Character Traits?

Have you ever noticed a character trait that has persisted in your being for a very long time, and yet cannot identify when, where, and how you came to develop it? Usually I can identify certain facets of my personality by referencing periods in my life where I adopted new behavior-driving ideas and was influenced by certain experiences, but lately I've noticed there are some traits which seem to have always been integrated within me, but I can't figure out how I came to develop them.

In my case, I've realized lately how much of my being emphasizes the proper use of manners in order to conduct my relationships respectfully, but I have no recollection of where I learned them or else decided to adopt them by my own judgment. It's like I've always been this way, yet I know that's not true; there must've been some point in my personality development where I began structuring these habits.

A particular elder once gloated how they were the one that taught me my polite ways, but I know that's not true since their usage of manners is insincere and for appearance only, whereas I'm sincere and am aware of the various outcomes that could result of my treatment. A child can absorb their elders' characteristics very thoroughly, not only adopting the physical appearance of the practice, but also the ideas and psychological workings that give rise to them to begin with. If I had adopted my manners from the practices of my elders, then I too would have adopted them for appearance sake, but I didn't.

To clarify what I mean by sincere, I mean that the manners are employed in an honest fashion in order to treat a person respectfully, and most importantly it's also recognized that manners may not always get you what you ask for and that you should continue your respectful behaviors in alternative outcomes. As a classic example, take asking someone for the use or consumption of their property, such as tasting their food. The respectful way to ask, though not necessarily in this concrete form, goes something like "May I have some of [such and such]," and it's up to the person to decide how he'll respond. More often than not the person with the food will say yes and offer some, but it's also possible that he may decline and prefer to consume it all himself. Given that it is his property it is entirely within his rights to do so. Someone with truly sincere manners will recognize that a person may respond in this alternative way, and will continue maintaining their polite behavior in face of this experience.

A person who's insincere and employs manners as a matter of appearance, however, will not anticipate the decline as an actual alternative and will start acting rudely after the experience. To them, they expect the answer to automatically be yes and don't know how to respond to this other answer. It's probable that in these scenarios this kind of person will drop their facade and lets their true rudeness show. I've once been in such a position where a person asked to taste my food and I preferred to eat it all. I declined politely and thanked them for their respectful inquiry, but they became completely confused and immediately resorted to intimidation and trying to induce guilt. To them, manners are just a matter of decoration: They expect their use to get them unfailingly what they want. Since insincere manners are in actuality rude, they might as well have come up to me and said "Gimme that!" or else directly taken the food. The person who gloated of teaching me manners uses them in this dishonest fashion, but I've never used them that way. So just how did I become this way?

Have you had a similar experience too, where you identified a personality trait you have no idea how it became part of you?