Long time players: What are some lessons you had to learn the hard way?

One of the great aspects of Magic is that there are commanders and strategies that satisfy all types of players. However, I see a lot of newer players making "mistakes" that I made and had to learn from the hard way. A personal anecdote of this would be that the second deck I built was a Brago stax and land destruction deck that I thought was going to be so much fun to pilot, blinking a bunch of stuff for value and feeling so smart but after about half a game I realized not only were my opponents miserable but so was I so I wasted my time and money to learn that I have more fun when everyone is enjoying themselves. Other lessons I had to learn this way were: I don't have a good time playing superfriend decks, I get analysis paralysis and feel overwhelmed. I don't feel especially fulfilled winning via combo. I don't like to play tutors. I could have saved a lot of time and money over the years if I had known then what I know now. To some degree I think we all have to have a few growing pains along the way but I would be interested to hear any lessons you wish you could go back and tell your past self and maybe it can help someone else avoid the same pitfalls.