It depends. For quick specific actions it is a proper method to make people feel bad. Examples: "Fire! Get out!" Or "Hot September! Sign petition here!" Howeve

It depends. For quick specific actions it is a proper method to make people feel bad. Examples: "Fire! Get out!" Or "Hot September! Sign petition here!" However, if you want people to find creative solutions to complex problems, a positive message works better. "Yes, we can!"