Not knowing how to stand properly.
Oh so often do you see players standing with a poor posture that does their game no favours. As Robbo and many other top guys say, the most important thing in ball you need to be aware of is you position and how much your present to your opposition to get shot at. Standing with your legs about shoulder width apart in a lose but well grounded way that is side on to the barricade would most players a lot of favours. Standing correctly helps snapshotting, maintaining accuracy as well as allowing ease of motion from your bunker. So many times have i seen players get eliminated by foot and knee shots that could have been easily avoided by paying more attention to how they were standing.
Look at this knob-head and how he's standing.
Look at that leg!! It's almost in Birmingham! It comes as no surprise that at this tourney he got taken out in two games with a foot shot and a knee shot. Fair enough he took out 3 people including one bunkering in this game but that could be easily attibuted to luck. More practise is needed, Nexus' seminar would we very useful for this hapless individual who a few months ago used to be able to stand straight.
by the by......that's me that is