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Could it be that,
"He hates it when people are late."
"He likes it when people are on time."
are correct but informal?

And,
"He hates when people are late."
"He likes when people are on time."
are always wrong?
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""He hates it when people are late."
"He likes it when people are on time.""

This usage of it is peculiar to English even though similar structures are often incorrect in other languages. I have seen some non-native grammarians refer to it as "formal object". I see nothing informal in it, apart from the fact that it may occur more often in spoken English than written English.

CB
Comments  
All four sentences are okay.