What is the biggest pain if you are developing your robot?

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Hi guys,

I have some experience with machine learning and computer vision, but I'm a rookie in robotics. I'd like to ask you what it is the biggest pain if you are developing your robot especially in connection with ml and cv?

I'm thinking about tool that can help specify robot's behaviour visually something like workflow manager where you can work with components. This workflow could work as the higher specification for robot's mind. What do you think about that? Do you have any suggestions?

Thanks a lot