First of all, I'm a newbie so excuse my stupid question but I have to know :(

I notice a lot of people say this, especially those who play a lot of poker.
I'm not really a poker player, but I know the game. You get 2 cards and the dealer gives you 5 cards from which you can choose 3 to build your hand. How does this require any skill? To me it sounds pure luck. You get good cards you win, you get bad cards, you lose or skip the round... Am I missing something here?