Agreeing to draws in the middlegame, equal or otherwise, deprives you of the opportunity to practice playing endgames, and the endgame is probably where you need the most practice.

Since your mental state can have such dramatic effects on your body, obviously your physical condition can affect your mental well-being. It follows that regular physical conditioning should be part of your overall chess training.

I had a slightly inferior endgame that probably should have been drawn, but Kortchnoi kept torturing me with little threats until finally, exhausted and exasperated, I made a losing mistake.

There is nothing wrong with trying to exploit the natural human tendency to become impatient when forced to play a boring position.

Sometimes players need to gain time on the clock by repeating the position, but most often its purpose is to wear down the opponent psychologically.

Agreeing to draws in the middlegame, equal or otherwise, deprives you of the opportunity to practice playing endgames, and the endgame is probably where you need the most practice.

Errors have nothing to do with luck; they are caused by time pressure, discomfort or unfamiliarilty with a position, distractions, feelings of intimidation, nervous tension, overambition, excessive caution, and dozens of other psychological factors.