You can’t invest full-time. For those who invest full-time, what they earn is not necessarily excess returns, but mostly management fees.

Because many times you may earn a lot of money in a good market, but at that time you think that it is because of your ability. Once the environment is bad, everything will fall back.

When it falls back, this feeling is the most fatal.

So investing must be done part-time, in order to understand the world and to have some fun.