- Friends. Friends are good. You hang out with them, you have fun with them. Friends also come in many different flavors and skills, some of whom are not particularly useful to your project. There will be a certain percentage of them who could be useful. You are in the tech industry, and naturally, a handful of your friends could also be in the tech industry. Your conversations with them clicks more than the gal/guy you tried to pick up at a bar last weekend. Does that mean that you and your friends can immediately start something big? Unless all of you operate in the same wavelength for at least 6 months, it's difficult to encourage your friends to start a project. Your friends might have different ideas. Your friends might have different opinions. They have different priorities in life.
- Coworkers. You are working with great talented people. It's naturally easy for you to stir something up at the workplace during those lunch and coffee breaks. You talked about how to improve the company's existing broken procedures. The conversations would later evolve into "wouldn't it be great if.." chatters. However, the same situations with friends could apply here with coworkers. Your coworkers must also have the same vision as you. Although it's a bit easier to team up with coworkers because you work in the same industry, sometimes the stress and the amount of work at work can kill your side projects fast. I once had this great conversation with my coworker of creating one game. We both agreed what it should be like (that's rare!), but we never had the time to actually sit down and do it. Our schedules were so far apart. Additionally, depending on the company you work for, the country, and the state/provincial laws, the non-compete clause in your employment agreement can prevent you from achieving your goals. The company wouldn't like if you are making another game that could directly/indirectly compete with their games. And yes, they could actually pursue legal action against you, if you ever break that agreement.
- Family. Family members tend to work in similar fields. Your visions and perspective of life are alike. Family-owned businesses can be successful. The Wachowskis and Coen brothers are among of the several examples where siblings can coordinate and be successful together. But, this also means that they could have the most arguments among each other. They can also plunge into the tar pit far faster than any other teams, thanks to the argument last night about who gets to keep Fluffy the dog.
- Strangers. Don't even try unless you are ready to pay them money.