For 2 startups - For first one, got ditched by the other founders. Lesson learnt, make sure everything is in black. For Second one - Support, you may have the

For 2 startups - For first one, got ditched by the other founders. Lesson learnt, make sure everything is in black. For Second one - Support, you may have the best product ever and the best implementation team on this side of planet, but the customer support is paramount. We gained too many customers too quickly and our support was stretched thin, hiring new employees to train them on an exotic platform was not easy. Also learnt that product simplification is the key to product design and success. Also, a lot of other reasons, but these were the prime one. It was well worth the time and would give it another shot someday. Edit : added some more text