My parents don't listen to my emotions and venting. How do I make it so they stop saying “its not that bad” or something else avoiding how I feel?

Most parents are unable to understand what their kids are going through just because everything seems "normal" to them. It's always necessary that what one's feeling is visible and that's why parents feel like everything is okay, even when it's not. Even to this day, it's very difficult to tell my parents what's going on or what's bothering me. Either they won't take it seriously or even if they do, which is very rare, they won't believe it or will think it's not that bad. It can be hard to really let someone know what or how exactly you're feeling , one thing you can try is letting them know that you just don't feel okay about their not listening to you or letting you tell them something. It doesn't have to sound rude or selfish,just a simple and polite request. You have the right to be heard.