気が進まない (reluctant, not in the mood)

The idiomatic expression 気が進まない (also 気がすすまない in kana), literally 'one's 気 (mind, will, inclination) does not advance,' meaning 'to be reluctant, hesitant, not in the mood to do something.' A softer, more inward way to express unwillingness than やりたくない ('don't want to').