It's really hard to appreciate life when you're going through tough times. It's really hard growing up and getting the hang of how things work. I haven't always appreciated life, not at all, but I see a bigger picture now so my perspective has changed. It happens to everyone that lives long, and/or hard, enough. A lot of older people are grumpy so in the end it's all in your perspective.
We only live right now. Before and after right now does not exist. Now, right now, is all there is. Yesterday is a memory. Tomorrow hasn't happened. There is only right here. Right now. You can argue against it and try to live in your past if you want but since it is impossible... seems like an awful lot of wasted time.
I get what you're saying. We learned stuff along the way but that wasn't us and that wasn't now. That was for them. Now is for us. We wake up and know what we know today. We do what we can with what we know today. Here we are. It makes no difference how we got here or where we're going. It only matters what we do right now.
Not one event has ever been "caused by past events". Everything is happening right now.
Yesterday is gone. Heck, this morning is gone. When I started writing this is gone. Nothing you can do will ever stop time. Learn and move forward or be stuck in memories instead of what's happening now.