Patanjali's yoga sutras

When your mind dwells on pain,

you are practicing attachment

and you suffer. When your mind dwells on pleasure,

you are practicing attachment

and you suffer. When your mind harbors anger and hatred,

you are practicing attachment. You become fettered to suffering.

Alberto Villoldo

Sukha https://en.m.wikipedia.org/wiki/Sukha

According to Monier-Williams (1964), the etymology of sukha is “said to be su [‘good’] + kha [‘aperture’] and to mean originally ‘having a good axle-hole’”; thus, for instance, in the Rig Veda sukha denotes “running swiftly or easily” (applied, e.g., to chariots). Monier-Williams also notes that the term might derive alternatively as “possibly a Prākrit form of su-stha, q.v.; c.f. duh̩kha“, literally meaning su[‘good’] + stha [‘standing’].

Desire is dwelling on pleasure.

सुखानुशयी रागः ॥ २.७ ॥

sukhānuśayī rāgaḥ || 2.7 ||

7. Desire is dwelling on pleasure.