Excellent thoughts, Punnaimaran

There's just one more perspective as to why respect the elders - simply out of sheer gratitude.

The other day, my wife had a phone-call quarrel with her mom and my m-i-l was obviously incorrect -she was talking without facts - and it went on for a while, even got rough.

However, after the call was over, I asked my wife to cool down a bit and asked her a few questions like - why doesn't she consider the days her mom carried her to the doc, nights she kept awake etc, much like we do for our children

It worked and she agreed to "accept her mother's craziness"

I don't think respect is shown by "simply agreeing to all that an old one says" but in many other beneficial ways. Politeness is obviously one, taking care of needs is another. Difference of opinions do not take away respect, IMO