At the start of the game, one square on each side is defended by nothing but the king itself: f7 for Black, f2 for White. That makes it the natural landing zone for early attacks, and the reason so many opening traps, from Scholar's Mate to the Fried Liver, all aim at the same spot.
The classic raid: a knight jumps into f7 supported by a bishop on the a2-g8 diagonal. The king can't take (the bishop guards the knight), and from f7 the knight often forks the queen and rook sitting on their starting squares. Until your opponent castles, keep one eye on that square, theirs and yours.
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The knight on g5 and bishop on c4 both aim at f7, and only Black's king defends it.
Raid the weak square.
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