There is no question that the president has been showing more emotion in recent months, but the Charleston church shootings appeared to touch a particular nerve because they involve two difficult issues in his presidency: gun control, which he hasn’t managed to overhaul, and racial divide.

Emotion is an important weapon that the president hasn’t used enough. It plays a critical role in persuasion, whether it is getting lawmakers to support legislation or convincing employees and clients to go along with your plan. It engages audiences and makes a message memorable. Brain research confirms that memory works by attaching emotion to events. In my 15 years of coaching corporate executives, I’ve found that talking about feelings is one of the most difficult things to do for men and women. There are several reasons:

Many executives have a difficult time expressing emotion or even identifying feelings because work and feelings feel incongruous. I was recently helping a pharmaceutical executive who was preparing to talk about a failed clinical trial for a drug. He had mountains of data, but I asked how he felt about it. He paused and said, “Well it is unfortunate…”

Okay, I pushed to explain. Reluctantly, he discussed the years of his hard work. Pushed again, he elaborated — yes, disappointing because of the hope that it offered people suffering from cancer. He did care about patients, but they weren’t part of his everyday life. (Ultimately, he received wide praise for including those reactions because he needed to persuade senior leaders to allocate more resources to a related project and needed to win patient groups support.)

Still, other people are not naturally or culturally inclined to share emotions. I worked recently with an executive who was preparing to deliver a community talk on parenting. He said his father taught him hard work and perseverance, and he shared that his father, now in his late 80s, had recently undergone difficult surgery but was back in the gym just days later. He agreed that others might have given up, but he had a hard time saying how that feat made him feel. Finally, he confided that it was hard to applaud because in his world, it was what was expected.

There are other reasons executives don’t emote. Some fear it will make them look weak. A senior vice president of a financial firm told me that looking sympathetic when sharing a new strategy made her look open to alternatives when she was firmly resolved to make unpopular changes.

Still, others are afraid that opening an emotional door will produce a floodgate of feelings that will be embarrassing a la John Boehner or Steve Ballmer. They worry that emotions will alienate more than unify. In David Axelrod’s book, Believer: My Forty Years in Politics, the former senior advisor to Obama paints a picture of a president who talked policy but is more prickly and emotional than he lets on in public.

But when you are trying to win friends and influence people, there is nothing like sharing your feelings or acknowledging the feelings of others, even if you don’t share them. It warms you up, makes you human, makes you more likable.

It is hard to tell if Obama’s emotions will lead to the kinds of changes that he wants to be part of his legacy. But it will surely lead to a record that shows he really cared, just like the man he eulogized so eloquently on Friday.

Mary Civiello is president of Civiello Communications Group.