Ask HN: Looking back, what have you wasted lots of time on?

Personal life, career, dev work, trying to be "clever" about saving money: anything will do. What were/are some of the biggest time wasters in your life?

This is anonymous account, so can be candid about mine... Things I regret as of today:

  * Taking too many business/economics courses, e.g. Managerial Economics, Marketing, etc..
  * Some DevOps stuff, particularly Ansible
  * Django/Python - should've started with Rails
  * Failed side projects that I kept working on for a long time
  * Facebook - deleted it several years ago
  * TV - havent watch it for more than 5+ years
  * Porn - havent watched for several months
  * School, memorizing useless facts - nothing can be done about that, I suppose?
  * Studying Calculus/Linear Algebra because I wanted to go into AI/ML
  * Some video games

EDIT: added mine