To undermine yourself with language is an interesting concept. Implying that the way you talk directly corresponds to what you know, which is partially true—entirely true — however is that language is wholly part of you. Language is part of how you communicate; it tells a story of who you are. The way that you communicate through language changes depending on who you’re talking to.
When making conscious effort to shift phrases you use, it alters people’s perception of you. The controversial phase “you know” or to some “ya know”, is used to transmit to people empathy. Transporting you from a place of harsh criticism to a place of thoughtful acknowledgment. Saying, “You need to dress nicer,” instead of, “You need to dress nicer, you know,” is to talk in an inflexible and uncompromising way. But adding the “you know” gives you an empathetic voice. Adding the hedge of “you know” to your sentence conveys trust to your conversation partner. It’s a way of saying this is a safe and accepting environment. Softening your language this way encourages different viewpoints. Showing that you’re less set in your ways than if you were to omit the hedge entirely. Using “you know” as a discourse marker seamlessly organizes the conversation. It’s quite possible that without the phrase the conversation would lose all format. When complaining about someone sidetracking a conversation I would urge you to think about whether or not you made an effort to give the conversation focus in the first place.
Something else to consider is why it would bother people to tack this on to the end of a sentence. To me there are two very distinct reasons people have stated that this annoys them. The first reason is people refusing to let language change. The types of people who will go around saying things such as “back in my day” or “actually the proper way to use that is … ” which tends to just make one want to scream, but not change their ways. This brings into question what language should stay the same and what should change. Everyone has a different viewpoint on this topic, but one thing I think should be easy to agree on is that language evolves. If language is fluid and constantly changing, why police it, ya know?
The second kind of people who are upset by the phrase are those who feel that it’s pushing feminism back. This is much more concerning to me because to control the way that non-men speak seems more like a way of pushing feminism back. Is coming off sweeter damaging to women’s place in society? I think not. Perhaps everyone should just try and be sweeter. But I don’t fully agree with that either. The issue is more that non-men have developed a lexicon that is uniquely ours and to criticize it by saying that it’s the problem is the fundamental issue. The systemic and social problem is more with any men that have decided to act entitled to everything and belittle those who are not men. The problem is not something to be solved by diminishing women even more.