While working in various jobs over the course of my life, I've seen people do it right and do it wrong. Learning from those that did those (jobs)  already and seeing what works and what doesn't makes you learn THAT much more.

What burns the most is the ideas discussed with friends at that time, as I really no longer speak to them.

Example, using high speed film 1600 asa and pushing it a stop - THEN you convert the negatives to slides.  University of Miami, Dale labs, Simms street in Hollywood, Florida.

or

Working as a wire photographer for UPI and deciding to trying and form my own wire company, after getting pushed out by someone that didn't think it was important to cover a major sports team in South Florida ( Miami Dolphins). My friend speaks to another friend and THEY go and start a photo wire service, with no understanding of NEWS ethics or photojournalism. The funny thing about the name of the company was that these guys used the term "wire" in their name to describe the company. so if I were to start a business myself shooting pictures I'd call myself Ron the baseball card photograher, or Ron the stock image photographer. 

or

 Working at a Wireless Phone carrier and increasing orders leaving the floor and being shipped to customers faster than any where else in the country. Using my truck and a last drop off point for Fed Ex. 

One of the people listed above was instumental to me becoming a photographer, but on the same note was very very selfish to the needs of his business.  Learning things like what works, as in what to do and what not to do, as he would say "When in Rome do as the Romans"

Conflicts between family and friends going in to business together are a major reasons why the business would and can  fail. The contract and aggreements in writing are set-up to protect your relationship more so than your business, Each person knows what is expected of them and having agreements in writing protects the business and the parties, involved.