in islam the rendering of one's good deeds invalid cannot be based on mere opinion or analogy. the only authentic reports of a persons deeds being invalidated is of only by major shirk, ascribing partners to Allah azzawajjal. there is no evidence to prove that disrespecting parents will invalidate all the good deeds.
but it is of no doubt that disobeying parents is a grave sin. there are evidences from the quran and authentic sunnah for this.
it is mentioned in the sunan An-Nasai (2562)
The Messenger of Allah (blessings and peace of Allah be upon him) said: “There are three whom Allah, may He be glorified and exalted, will not look at on the Day of Resurrection: the one who disobeys his parents, the woman who acts in a masculine manner, and the cuckold. And there are three who will not enter Paradise: the one who disobeys his parents, the one who is addicted to alcohol, and the one who reminds people of what he has given to them.”
this hadith clearly states the enormity of the sin. the point what we must understand when we hear hadith like this is that, it is the end what matters. it's never too late to repent and try our best to abide by what has been decreed to us by Allah azzawajjal.
And your Lord has decreed that you not worship except Him, and to parents, good treatment. Whether one or both of them reach old age [while] with you, say not to them [so much as], "uff," and do not repel them but speak to them a noble word.[17:23] (sahih international)
And your Lord has decreed that you worship none but Him. And that you be dutiful to your parents. If one of them or both of them attain old age in your life, say not to them a word of disrespect, nor shout at them but address them in terms of honour.[17:23] (mohsin khan)
this is the most strongest verse regarding respecting parents. Allah azzawajjal is stating His decree that we must respect them. the reason why i have used two translations of the verse here is just to get a more clarity and a deeper understanding of the enormity of this warning. so when you say its not a big deal, this verse suggests other wise.
the scholars have all agreed regarding the sin of disobeying/disrespecting parents but as i said before, i have not seen nor am i aware of any authentic narration that says one's good deeds will be nullified just by committing the sin of disobeying parents.
- Shaykh Ibn Baaz (may Allah have mercy on him) said :
Disobedience towards parents is a major sin and a serious haraam action that must be avoided, but disobeying them does not render prayers, fasting or other righteous deeds invalid. However the one who does that is in danger because of this grave major sin. Good deeds are only rendered invalid by shirk.
(taken from : www.binbaz.org.sa/mat/9208)
however there is a hadith reported by At-tabaraani in Al-Mu'jam Al-Kabeer that says 3 things render deeds worthless and it mentions, disobedience to parents as one of the things. i have found that the muhaddith say that this hadith is weak. similar hadith is found in An-Nasai and Darussallam has graded it hasan. (more research is required to identify the strongest opinion)
may Allah the mighty and sublime grant us mercy and guide us to the straight path.
ALLAH KNOWS BEST