What a market maker actually does
Most people picture trading as betting on direction. Market making is closer to running a shop that never closes.
A market maker quotes two prices at once: a price at which it will buy and a slightly higher one at which it will sell. The gap between them, the spread, is the fee the market pays for someone always being there.
The hard part is not quoting; it is surviving being quoted against. Prices move, and a stale quote is a donation. So the job becomes a forecasting problem measured in fractions of a second, where the goal is not guessing where the market goes next month but knowing where the price should be right now.
Done well, everyone benefits: tighter spreads mean investors pay less to trade. Done badly, the market teaches you faster than any tutor.