Theory of Karma - Chapter 1

The track (GATIHI) of KARMA (ACTION) is mysterious (GAHANA).

Lord Shri Krishna has himself proclaimed in Geeta that it is difficult to understand the intricacies and indefinite extent and shape of Karma (Action), as it is so complicated,
intricate, zigzag, unfathomable, dynamic, inscrutable and mysterious because the life is such. The trail of Karma (Action) is jagged and intractable.

Shri Sudama, a friend of Lord Krishna says about the complex nature of Karma as under:

The working of Karma seems so complex

We two, the students of the same Guru (Teacher).
He (Krishna) became the king of this earth

While I have nothing even to eat.
He used to play with monkeys in Gokul

And used to fetch wood at teacher's house.
Now he sits on the throne today

While I possess only a begging bowl and a stick in hand.