The most pleasant collaborative experrience was financial for me... When I was a university student (in my penultimate year of study), I accidentally met the owner of the company that organized the graduation ceremony (selling togas, robes), and during the conversation he asked me to be "responsible" for my year in this process. I accepted, and it was very financially worthwhile. After that, I was involved in this "business" for years, convincing other years to work with this company. After 2-3 years, I was already active in other cities of the country. This partnership ended when the company owner became a senator and had to sell the company (due to a conflict of interest).