be another of life's great mysteriesbe another/one of life's great mysteries
humorous to be something that it is impossible for you to understand.
Why people write their names on the walls of public toilets is one of life's great mysteries.
be another of life's great mysteries
To be difficult to understand or decipher. This phrase is often humorously applied to unimportant things. The living cannot truly understand death—it's another of life's great mysteries.Why dogs and cats hate each other is another of life's great mysteries.