"Experts say it's expected many will feel angry with returning mask measures. It's very hard to pull the finish line away from somebody when it feels like they finally have the ribbon at the end in sight," American Psychological Association chief science officer Mitch Prinstein told CNN. "I think we can also understand the anger in the context of exhaustion, anxiety, uncertainty, and you know, a serious division of ideology too," Prinstein added. "These factors are very real and very concerning right now.""