Feeding a balanced diet and taking care of other pet health problems might also slow the development of all the problems associated with aging. (2ndchance.info)
They're busy and have a limited amount of time to interact and give feedback, which can slow the development process. (sciencemag.org)
In the opposite situation, when the team doesn't like the game they're making, the slightest problem slows development down a lot. (gamesauce.biz)