Going back to ~18-20 years old: focus more narrowly when building things. Focus overwhelmingly on business services/productivity and never go anywhere near cons

Going back to ~18-20 years old: focus more narrowly when building things. Focus overwhelmingly on business services/productivity and never go anywhere near consumer oriented services. Focus more on the process of sales generation and less on unnecessary (unintended) complexity & features. I learned the wrong lessons from the ~1994-2001 dotcom bubble era (as a teenager) and I wasted a bunch of years correcting various wrong ideas about business that I had picked up.