"You Better Think" -- Aretha Franklin

King and pawn endgames look like they should be easy but there is nothing easy about it. Some positions require much time on the clock. One little mistake can lose a game instead of getting a draw, or getting a draw when it should have been a won game.

Moving the King to the wrong square or moving the wrong pawn is very easy to do if the chess player doesn't take a long time to think.

Wikipedia - Chess endgame - King and pawn endings

King and pawn endings

King and pawn endgames involve only kings and pawns on one or both sides. International Master Cecil Purdy said "Pawn endings are to chess as putting is to golf." Any endgame with pieces and pawns has the possibility of simplifying into a pawn ending.

In king and pawn endings, an extra pawn is decisive in more than 90 percent of the cases. Getting a passed pawn is crucial (a passed pawn is one which does not have an opposing pawn on its file or on adjacent files on its way to promotion). Nimzovich once said that a passed pawn has a "lust to expand". An outside passed pawn is particularly deadly. The point of this is a decoy – while the defending king is preventing it from queening, the attacking king wins pawns on the other side.

Opposition is an important technique that is used to gain an advantage. When two kings are in opposition, they are on the same file (or rank) with an empty square separating them. The player having the move loses the opposition. He must move his king and allow the opponent's king to advance. Note however that the opposition is a means to an end, which is penetration into the enemy position. If the attacker can penetrate without the opposition, he should do so. The tactics of triangulation and zugzwang as well as the theory of corresponding squares are often decisive.

Unlike most positions, king and pawn endgames can usually be analyzed to a definite conclusion, given enough skill and time. An error in a king and pawn endgame almost always turns a win into a draw or a draw into a loss – there is little chance for recovery. Accuracy is most important in these endgames. There are three fundamental ideas in these endgames: opposition, triangulation, and the Réti manoeuvre.