Maybe everybody knows Tesla is going to win out, therefore everybody wants it, and the price rises like crazy. And then the stock is way overpriced for what you get, and people like you still keep buying it.

There is a reason why Buffet needs to look into the numbers before deciding if something is a good buy or not. You buy underpriced, and sell overpriced. And you just cannot make that judgement without looking at the numbers.

There is another simple theory about your single stocks outperforming the index: smaller cap stocks generally outperform the index. As shown in this video, a monkey can pick stocks and outperform the index just because of this simple reason: https://www.youtube.com/watch?v=5_3Ra-Q6vK4.