Why is it so easy to lose a winning position

Why is it so easy to lose a winning position?



Here is the game, I was winning then I completely blundered

oof...

You had an isolated pawn. An isolated pawn is considered a weakness if you fail at using it for an attack or threat in the middlegame and also don't know how to exchange or defend it properly. The engine doesn't show this because the engine knows how to do it. The second thing is you just completely ignored threats of your opponent. Rd5 walks straight into the line of blacks bishop - forcing you in a move sequence you never wanted.

"A won position is the most difficult to win" - Lasker
You need to stay focussed and keep thinking carefully. You start to deteriorate with 14 Qd3, inviting the good centralisiing move ...Ne5. You had 14 minites in this 16+6 time control game.