[smrtengineer]

among the reasons mentioned above, its also about going through a mental preparation before prayer.

It is said of Ali ibn al-Husayn that he used to turn pale when he made his ablution. When his family asked what came over him during his ablution, he would say, 'Do you realize before whom I wish to stand in prayer?'

Source: Inner Dimensions of Islamic Worship, Al-Ghazali pg.30

As well, due to this ablution, there is a hadith, that says the areas that were washed will glow on the Day of Judgment and the Prophet (saw) will recognize his people through their glowing bodt parts, which is a result of ablution.