I would guess most traders are aware of these levels such as the previous day/week/month high, low or closing price etc. and pay attention to them. There are mainly three things that can occur there: the level is respected (tested), price penetrates the level but fails to continue in its course (failed breakout), or it breaks the level and keep going (successful break out). This is all there is to trading. Congratulation you have solved the puzzle. :)