Everyone always has something to say about everything. It's just human nature that we always want to contribute to the conversation, or to someone's life. When people ask you about school, or your job, or your relationship, they want to be able to offer something to you that might make things better or easier. It's always packed with good intentions, but sometimes good intentions aren't enough to keep you from getting frustrated.
No matter how well-intended or kind-hearted someone's advice to you might be, there are going to be times when it's the five millionth time someone has asked you if you really thought this through, or have you thought about doing this whole other thing that isn't anything like what you just described. And the people who are the most passionate about their opinion being the right one, are usually the people who have no experience in what they're advising you on.
The people who are telling you to switch your major never took a single class in your field of study. The people who are saying that you should shoot straight through undergrad into grad school without taking a break are the people who never even considered getting a master's or a doctoral degree. Everyone telling you that you're going to have to give a certain thing up to pursue another thing, that you won't be able to juggle whatever it is you're planning to juggle, has probably never done any of the things that you're planning to do. Not that that stops them from offering up their point of view.
It's well-intentioned, but misinformed and frustrating nonetheless. It's especially frustrating when it actually makes you question and second-guess whatever your plans are. We're plagued by enough internal insecurity when making big life decisions, we usually don't need any assistance from outside sources.
I struggle a lot with this. I'm caught between appreciating advice from informed sources, but also letting viewpoints that go against my plans make me incredibly anxious about my decisions, even if the person who is disagreeing or debating with me has no idea what they're talking about or what is going to go into the plans that I have. It's a "me problem" as much as it is a "them problem".
But we can't change people. We can't change human nature.
Unsolicited advice will always have the potential to be as annoying as it is helpful. But people will always be full of it. Even those of us who are annoyed by it are going to be full of it from time to time. I'm not at a point yet where I don't let it affect me. I get skittish and nervous when someone essentially asks me, "Are you sure that that major life decision that you made is a good idea?" Because, well, no, I'm not. None of us are. But there's comfort to take in the fact that none of us have a clue about what we're doing or where we're going, we're just figuring it out as it happens. There's no shame in that.
I work every day not to let these little "pearls of wisdom" cause me more stress than they're worth. It's easier said than done. When people try to advise me to do the opposite of what I'm planning to do, or ask me if I think what I'm doing is a good idea (because, you know, we all want to follow through on things that we think are bad ideas, obviously) I do my best to smile, nod, and move on from the conversation. I'll tell them, "Yea, that's something to think about," or, "This is my plan for now. It might change but for now I'm sticking to it," and any other variation of something that essentially tells them that I'm done with whatever discussion they're trying to create.
Dismissal is the easy part. The difficult part comes afterward. Once you dismiss the conversation, you have to remove it from your brain as well. You can't let people's doubtful comments and questions hold you back from doing what you want to do. Even if their doubt is technically coming from a good place, you have to work to not let it carry enough weight to make you undo the work and progress you've already put into your plans.
We work hard to try and figure out who we are and what we want to do. We spend our entire lives putting together that picture. It takes a lot of work and thought, and a lot of internal conflict and second-guessing. We put ourselves through enough of it, we owe it to ourselves to not let other people put us through it too. Whatever it is, whatever we're meant to do or become, we'll figure it out. And we'll figure it out on our own terms. Don't let other people's viewpoints cause you to doubt that.