How do you win in a chess if you show your intentions right away?

If your opponent already knows what you're up to, how can you go around it and win? It might seem real foolish, especially since the intentions were purposefully set forth in an obvious manner, just so they would be known.

Well what if the other option may allow you to play the game with small chances of victory but the looming threat that you would forever stay as just a chess mate to your opponent? Nothing more than someone who he/she plays chess with occasionally (or not)?

Maybe the read on the situation wasn't clear enough to realize one option heavily outweighs the other, but at the same time, availability heuristics has clouded judgement and who is to blame since heuristics is always our first course of action, even though it is often bias and incorrect, as compared to algorithms?

Is it even possible to base one's thinking and decision making purely on algorithms?