I saw a TTC recently which stated that resting his army after defeating the Scandinavians would have been the obvious thing to do. The implied selfishness (due to him wanting to protect his estates over resting his men) was hinted as being a reason his army may not have been as committed as they could otherwise have been, hence contributing to the reasons for the battle being lost.
In hindsight, do Harold's actions seem selfish? Maybe. But did Harold have a choice? Not really.
Early medieval kingship functions on displays of strength, wealth and power. Like governments today, an early medieval king who couldn't effectively project an image of strong and stable rule could place his reign in jeopardy, and the simple truth is that England was under attack in 1066 and Harold simply couldn't afford not to act.
The reign of Æthelred the Unready some 50 years earlier had been marked by Æthelred's continued apparent inability to effectively deal with the Norwegian threat, which was both exacerbated by, and then wildly inflamed, political divisions within England. As provincial nobles became increasingly convinced of Æthelred's inability to defend their territories, so they in turn became increasingly reluctant to support him. Harold's own predecessor, Edward the Confessor, had similarly been dogged by his own power struggles with Harold's father, Godwine. Harold's own grasp of power in 1066 was far from secure, and depended largely on the continued assent of England's nobility, especially when Edward's rightful heir, Edgar Ætheling, was close to coming of age. If Harold allowed Norman raiding to continue unopposed, he'd risk looking too weak to rule effectively, all the moreso if it was his own personal estates which were under attack. After all, if a king cannot protect his own hearth, how can he protect a whole kingdom?
The Anglo-Saxon army actually performed very effectively for most of the Battle of Hastings. Even Guy of Amiens Carmen de Hastingæ, which is usually less than complementary about the English, talks of how effective the English shieldwall was and the difficultly of the Normans in trying to breach it. The difference comes down to methods of generalship. The same English tenets of kingship which demanded Harold go to battle also demanded that Harold lead his men from the front, which in turn meant fighting on foot. This meant that, compared to the mounted William, Harold was unable to proffer effective and rapid command and control to the different wings of his army, which were thus expected to function essentially autonomously, and this left him unable to restore control after his flanks were lured out of formation by Norman feinting tactics.