pray tell

For demanding an answer. In my opinion, it adds a friendly layer of irony, indicating that you cannot see a possible reason for something :

And pray tell, what purpose does it serve? 🙄

Half Sisyphus, half rolling stone.

Describes self sabotaging tendencies (while showing good will and effort).

I thought you quit smoking last month – yea, half Sisyphus, half rolling stone🥲