The winner is the athlete who has the most points after ten events. So the decathlon is the only event in which it doesn't really matter if the athlete finishes first, third or worse in a particular event. The score is the thing and the decathlete competes against a scoring table, and in reality, against his own ability and standards. Few major international meetings will ever be won with a score of less than 8000 points. There is some subjectivity within the scoring tables.
Mental factors play a greater role than they do in other events.
In the decathlon there are chances to recuperate from mistakes. Decathletes also differ from most athletes in their reaction to a completed meet. Ask a decathlete to assess his recently completed performance and invariably they are seldom satisfied, in fact, often frustrated. No matter how well he does, whether he wins or sets a record, the decathlete can always find room for improvement. Additionally the decathlon is the most neighborly of all track events.