Father's Right

The Messenger of Allah (sal Allahu alaihi wa sallam) said: "A son could not do enough for his father, unless he found him as a slave and purchased him to set him free." [Jami At-Tirmidhi - graded sahih]

Securing the freedom of the father from bondage, although an extremely virtuous deed, is in practical terms a rare occurrrence. As such, it is next to impossible that a person can fully acquit himself of obligations towards his father through his various acts of dutifulness. This is even more true regarding obligations towards one's mother.