The most important lesson in life is seeing reality as it actually is rather than how you imagine it to be or how you want it to be.
Once you can see this you can do anything. It's the starting point. Figure out what's true and then you can go from there. But until you figure that out you get hopelessly tangled up in webs of your own weaving.
Since many folks know I'm a philosopher and read things like Jed, they read what I wrote above and get hopelessly lost in the perceiver/perception/perceived problem. They immediately say who can really know what's true and hence get stuck not knowing.
Others are stuck in believing that belief itself is noble. I'm this, I'm that. It defines me. They have the unfortunate belief that holding onto their beliefs at all costs is noble and even the will of the divine + hence they got stuck, unable to grow or change their whole life.
Still others never reflect at all on the thoughts moving through their head. They think their thoughts are real + every thought is them. I think it or feel it + therefore it's real. This is a path to misery. Our thoughts can easily be discarded because they've no real substance.
There are some who mislead others because their rage + thoughts have become so real to them that they want to force that delusion on everyone because it must be real! They are the most dangerous people on earth + create the greatest misery for themselves + everyone around.
When we cling to beliefs that aren't real we can't help but create pain for ourselves. We might stay in a marriage that's wrong for us or continue down a career path that makes it painful to get out of bed everyday or lead a war against people who just can't "see" the way we do.
In the end, the more you can adjust what is in your mind to match what you see outside the easier and more effortless your life becomes. The more you continue to try to force what is in your mind on everything around you the more you suffer.
There is no path to joy that does not go through self understanding.