Here's one of the biggest reasons why nobody wants Trump to speak at their memorial service

The U.S. is one week into the memorial services for the late Sen. John McCain (R-AZ) and while Democrats and Republicans alike have publically delivered eulogies and tributes to the former war hero, President Donald Trump has been notable by his absence.

While the Washington Post noted that Trump is considered by many to be a "pariah," and believed to be left off the guest list for McCain's funeral to make a political and personal point, Politico reports that Trump is often shunned when the focus of a gathering is someone other than him.

The reason? He can't stop talking about himself.

"When Barbara Bush was laid to rest in April, word went out that he was persona non grata. And now, as Senator John McCain lies in state in the Capitol rotunda before Saturday’s services at Washington’s National Cathedral, Trump has also been asked to stay home," writes Politico's Gwenda Blair. "There aren’t too many ways of snubbing a sitting president, but this is one of them and McCain, who planned every minute of his multi-day memorial, wasn’t going to miss the chance."

According to Blair, McCain spared his mourners the prospect of the president making the funeral all about himself, if Trump's history at memorials is any guide.

Specifically, the way Trump conducted himself at a 1999 memorial following his father Fred's death.

With more than 650 people attending the service at Marble Collegiate Church in Manhattan, Trump followed his three siblings paying tribute to their father by bragging about his own successes.

"When it came time to eulogize his father at the funeral, the focus shifted noticeably," Blair writes. "He began by saying it was the toughest day of his own life. It was ironic, he said, that he’d learned of his father’s death right after reading a front-page story in the New York Times about the success of one of his own developments, Trump Place. He then enumerated all his other projects and said his father supported each one, and he finished by noting that on everything he’d ever done, Fred had known he would be able to pull it off."

"The funeral of Fred Trump wasn’t about Fred Trump; it was an opportunity to do some brand burnishing by Donald, for Donald," she pointedly added. "Throughout his remarks, the first-person singular pronouns—I and me and mine—far outnumbered he and his. Even at his own father’s funeral, Donald Trump couldn’t cede the limelight."

You can read more horror stories about Trump attending memorials here.