I heard this and thought this is a great piece of advice for young and old.

Being critical is a natural thing sometimes and we may not even realise we do it, however this breeds negative practices and being overly critical means we cannot harbour positive influences.

so never criticise

1 Your Fate. (It might be better to be thankful for the condition you are in)
2 Elders infront of children (Children learn from you and how you respect your elders sets their brain in the same mindset)
3 Condition of home that you own (This is similar to the analogy that those in glass houses should not throw stones)
4 Your mum and dad / elders (Your parents have raised you and sacrificed a lot to get you to where you are now)
5 Inlaws infront of your wife (Your wife’s parents have raised her and sacrificed a lot to get you to where you are now)
7 Friends to strangers (you should not speak badly about friends anyway, but to strangers is a no no)
8 Rukhsad / mehmano ki (assuming rukhsad means dinner/meal at a guests house. I take this one stage further and usually dont criticise food unless its really bad. But doing this at a guests home is bad mannered)

Thats all for now folks!