I have chosen the way
I have set my heart
on your laws.
It takes a conscious effort to "set my heart." I have to wake up with God on my mind and His will in my heart. Even at my ripe old age, I am still being teased by the evil one and my heart begins to divide. The main part is still God's but the periphery becomes segmented.
Usually I recognize that the struggle is evil and tell "it/him/her" to flee. However, sometimes I'm grabbed and taken down for the count and turned into a monster (and I don't even like to wrestle.) I don't like monsters and my family, friends and co-workers don't either.
As you see from the Psalmist, we have a choice.