You can't control what other people think or say, but you can control how you respond. I think I learned that from some TV character in anger management classes

You can't control what other people think or say, but you can control how you respond. I think I learned that from some TV character in anger management classes, but it seemed like a good nugget of wisdom. I don't think it's a wise idea to get grumpy (particularly visibly grumpy) with people who make unreasonable change requests. They don't do it to be mean, they do it because they are ignorant. So, it's up to you to educate them - try not to be condescending, try to be enlightening. Take them down the rabbit hole and show them what you can do quickly, and what takes time, and why. When someone asks me to do something, I like to present multiple options to achieve their objectives, highlighting easy ways to do things that may have drawbacks, but take less time, and also fully explaining the time and costs of their intial thoughts. The key, I think, in working with business people on software is being obviously willing to do some work to achieve their objectives, but also offering a pragmatic, technical point-of-view. Don't leave them room to think you just don't want to do something - express that you are definitely going to do something, but guide them to the right path.