There’s no rhyme or reason to/for something
Definition 1 of 1
Pro Tip 1/3Idiomatic Expression
Used to express confusion about why something happens without logical explanation. 
I can't see why she's leaving such a good job; there's no rhyme or reason to it.
Pro Tip 2/3Not Always Negative
Though it suggests randomness, it isn't strictly used in a negative sense and can denote wonder. 
The artwork was strange, a mosaic of colors with no rhyme or reason, yet it was captivating.
Pro Tip 3/3Figurative Use
Remember, it's not about poetry or reasoning literally; it's a metaphor for lacking logic. 
The plot twists in the movie had no rhyme or reason, leaving the audience confused.