One of the biggest challenges I have faced when working with Node-RED is debugging. Node-RED is a visual programming language, which makes it difficult to pinpoint errors and bugs. For example, I was recently working on a project that involved sending data from a Raspberry Pi to a cloud platform. I had a few nodes set up, but I was getting an error when trying to send the data. After some trial and error, I realized that the issue was due to a typo in one of the nodes. If I had been working with a more traditional programming language, I would have been able to quickly pinpoint the error. However, it took some time for me to find the issue in Node-RED.