Digging in and putting up a fight is a great way of turning poor positions around, not least because of the psychological pressure this puts on your opponent. The logic behind this (rather than just playing for swindles) is beautifully described by Paul Keres in the chapter on defending difficult positions in The Art of The Middle Game. But what Keres does not mention is that the personal character trait one must cultivate to do this is a tolerance for psychological pain.
Pain tolerance is high on the list of unsung qualities that make a good chess player. Not many people have this, instead preferring to make a quick getaway should their position be bad and unpleasant to play. So they try for a swindle or two and then go down the pub to drown their sorrows, which needless to say is far from optimal.
Some research (Dr. Jon-Kar Zubieta’s et al – “COMT val158met Genotype Affects u-Opioid Neurotransmitter Responses to a Pain Stressor” – February 2003) has indicated that pain tolerance is largely genetic, would this also encompass psychological pain? Another question is whether or not it can be cultivated? I think it’s very possible, though the methods one might use to do this might be a bit oddball.
First of all one might try gradually getting used to unpleasant situations, for example I understand that one former Soviet Grandmaster recommended taking cold showers. There are probably other ways to do this too, for example there are many instances in life in which one has to choose between the ‘easy’ (short term painless) option and doing the right thing. Telling the truth is an example and it wouldn’t surprise me if good defenders were also more honest than average.
Secondly I think it likely that improving one’s general state of mind and health may help; healthy and happy people tend not to let things upset them too much and will consequently feel fewer negative emotions when their opponent has them on the rack. How should someone achieve this blissful state? Probably the usual stuff of gentle aerobic exercise, learning how to meditate and eating more vegetables…