If there's one thing we've learned about Donald Trump through this campaign, it's that, for better or worse, the man can hold a grudge.

And hours after winning the Republican nomination, Trump was celebratory, yes, but also in a mood to call out his enemies — mainly the guy who wronged him this week, Sen. Ted Cruz (R-Tex.).

Trump spoke to Republican National Committee volunteers on Friday morning in Cleveland, where he spent a significant amount of time insulting Cruz after the runner-up gave a speech where he refused to endorse Trump.

Cruz's speech, we'll remind you, gave him an opportunity to put the past behind him and urge America to vote Trump. Instead he said this:

Trump's campaign was criticized for letting Cruz give the speech in the first place. His campaign staffers admitted they saw it beforehand, but on Friday Trump tried to pass blame by indicating Cruz added in the objectionable parts.

"He got up and he added a sentence, which could have been viewed as a nasty thing," Trump said.

What Trump's implying here seems to be incorrect. Members of The Fix team, including me, who followed along Cruz's prepared remarks found no such example of Cruz making off-the-cuff remarks about Trump. The sentence Cruz did add immediately after congratulating Trump was this: "And like each of you, I want to see the principles that our party believes prevail in November."

Not a full-throated embrace of Trump, but hardly the kind of snub Trump indicated Cruz ad-libbed.

Anyway, that whole drama happened Wednesday. And here we are on Friday, still talking about it. That's because Trump spent so much time going on about Cruz that if you were suddenly dropped from outer space and forced to watch CNN on Friday morning, you would think America was still in the middle of a hard-fought, incredibly acrimonious and personally offensive primary campaign between the two men.

On Friday, Trump brought up rumors — again — about Cruz's father. As we talked about here, they are Just. Rumors.

Cruz is widely believed to be planning a 2020 race, regardless of whether Trump wins. Trump wondered aloud if he could fund a super PAC to bring Cruz down.

Or maybe, Trump wondered, Cruz's career is over anyway after what he did for him. (Cruz & Co. see it very differently.)

It's not like Trump will have one flash of anger with a microphone in his face and this will all be over. In an interview taped Thursday with CBS's Ted Koppel, Trump called Cruz being booed "beautiful."

"And he did get booed of the stage, and I think that’s a good thing as far as I’m concerned, because I let him speak, I gave him a home, because I defeated him soundly, I mean by millions and millions of votes," Trump said.

Trump lobbing insult after insult at someone who attacked him is true to form, based on what we saw in the primaries. But it made a little more sense back then, you know, when he actually had something to gain from it. As of this week, those primaries are officially over. Trump won. Cruz didn't. Other than the fact Trump holds grudges, we can't understand why he's still harping on this.

Ironically, while Trump was talking Friday, he gave himself the best piece of advice to get over this feud and allow him, the party and us, the media, to instead be talking about his upcoming battle with Hillary Clinton:"For any of the people we beat so bad: You have no choice. You gotta go for Trump."

In other words, the primary is over. Drop it.