Self-improvement via a PSI course is not only painless, but is evaluated with high marks by the students.
ASJC Scopus subject areas
Barrera, M., & Glasgow, R. E. (1976). Design and Evaluation of a Personalized Instruction Course in Behavioral Self-Control. Teaching of Psychology, 3(2), 81-84. https://doi.org/10.1207/s15328023top0302_10