Mahendran,
Just the fun of it.
Remember they are not perfected in wisdom, far from it. They got that deva birth through one or other good deed, mostly generosity. It is like a good-natured and generally well-behaved graduate with higher education teasing or taunting a colleaugue because he has nothing better to do. Still a schoolboy at heart.
Most of them are not on the Path. They have no idea that their stay there will end, even unexpectedly,so they are given to such nonsense at times. There is a sutta where a certain deva was enjoying himself with one thousand ‘dove-footed nymphs’. Suddenly 500 of them disappeared there and then. He went looking for them with his deva eye and saw they had appeared in an apaya – one the hells, if I remember correctly.
For the rest, I am with what Akvan says.
Metta