Malcolm Myatt, a 68-year-old grandfather from England, is smiling a lot these days. And with good reason. After doctors told him a stroke had affected the part of his brain that controls emotions, he and his wife, Kath, realized he could no longer feel sadness.

"I am never depressed. Being sad wouldn't help anything anyway," the retired truck driver told The Telegraph. "I would definitely rather be happy all the time than the other way round. It's an advantage really.

"The stroke could have become my worst enemy but I wouldn't let it," added the man dubbed "Mr. Happy" by the British media. "Now I barely even notice that I don't feel sadness.”

Kath Myatt told reporters that her husband's "childish" behavior is "infectious."

"When he starts laughing everyone in the room does," she said. "If he's in hysterics, everyone else is too. He livens up any room. Everyone misses him when he's not there."

The American Stroke Association confirms that, because a stroke impacts the brain, a victim's personality can be affected. But, generally speaking, depression is the most common emotional change experienced after a stroke.

Myatt suffered his stroke in January 2004, after which he spent 19 weeks in the hospital. His wife also said he's lost the ability to judge what is and isn't appropriate to say in public.

"It's worst when we go to a funeral. He'll still be smiling and telling jokes while everyone else is completely somber," she said. "Most of the time people know him and understand, but we do try to keep him to one side just in case."

Over the years, strokes have impacted people in a wide variety of ways. Only last year, a 27-year-old British man named Chris Birch said he woke up gay after suffering a stroke.

Every year, some 15 million people worldwide suffer a stroke. After dementia, stroke is the second leading cause of disability.