Keep It Simple
"The best laid plans of mice and men/ Go oft astray..."
Go is a complicated game. Go players often feel a need to push themselves to make complex plans in order to adapt to the game. But at some point, we need to rely on our intuitions and not lose track of what we're doing.
For example, when reading out the life and death status of a corner, evaluating the status thoroughly once is enough. If after your first evaluation you continue to re-read the status every turn, you will forget everything you read out on your first try and eventually manage to confuse yourself with a complicated line that includes several errors.
Or, when defending a group, you may realize that it is absolutely necessary to play a vital, but decide that you want to try to make a few sente moves first just to show your opponent who's boss. But if just one of those moves isn't sente, or if one of the sequences goes in an unexpected direction and you lose track of the flow of the game, your opponent will return to kill your group.
Perhaps you have realized that you and your opponent have both misread a fight, and a large, apparently living group is actually unsettled. The simple thing to do is to recognize that this is the biggest move on the board and play it. The complicated thing to do is to continue to play the endgame normally so that you don't miss any of the big endgame points, assuming that your opponent won't notice that you made a mistake.
You may have an obvious shape move that would give you a good result, but would give you an even better result if you could get in a few moves in sente on other parts of the board first. Your complex plan for getting the best possible result is only better than the simple move if you assume your opponent will leave the good shape move open for you.
Any plan that starts "If I get one stone here and another move there..." may be too complicated. Your opponent gets to place a stone every time you place a stone, and you forget this simple equality at your own peril.
Simple play is partly about trusting yourself, and partly about respecting your opponent. If an absurdly complicated plan falls apart where an simple, straightforward move would have worked, the player who blundered will be embarrassed and possibly grouchy; this is why simplicity is a good habit.