That's another tricky question. Naturally, when we are not feeling good, others happiness might look like a threat but if one is consciously aware, then you should know that what you see as a threat should be an inspiration to hustle smartly.

Don't ever envy those who are doing far better than you cos with such mentality, you are already a threat to those who you are doing better than .

Live and let others live too

I am indifferent about other people's happiness.
Not unhappy and not happy. I simply may not care or feel one way or the other.
Not my business per se.