Children who are neurologically atypical are often extremely sensitive to changes in their routine, criticism (even when it's gently worded), and small disruptions from their expectations. For children with conditions like ADHD, what looks like a tiny blip in an otherwise great day can loom large and turn into a real problem.
Understandably, parents can be extremely frustrated by these reactions. After all, eating from the red bowl instead of the blue bowl or sleeping with two pillows instead of three doesn't seem like a real problem. Many parents and bystanders insist that the child just "get over it" and go about their day, but many children will insist that they can't do that. Instead, the disruption will be the trigger for meltdowns, tantrums, and emotional distress that can last for hours.