Is ablution a matter of extravagance or thoroughness?

Performing Wudu thoroughly means circulating water over all the parts of the body designated for Wudu such that it flows over them. This is something desirable in Islamic law, and by it, Allah expiates sins and elevates ranks. As for extravagance in water, it is transgression in purification, and it occurs by using water beyond necessity, or exceeding the prescribed number of washes, or exaggerating in seeking purification, which may lead to obsessive doubts (waswas).