This document discusses lessons learned from various business ventures and startups. It describes 5 stories of companies or products the author was involved in from the late 1980s to present. Each story is followed by 1-3 lessons learned from that experience related to seeing opportunities, avoiding bad partners, failure leading to new opportunities, timing, sustainable business models, fully committing, scratching personal itches, success being non-transferable, managing early excitement, and doing market research. The overall lessons are applied to the author's current company, AdDuplex.