The North Carolina men's basketball team's domination of Clemson in Chapel Hill falls under that second category.
The Tar Heels have never -- that's right, never -- lost at home to Clemson. The scoreboard reads UNC 46, Tigers 0.
Clemson will take its annual stab at ending the skid tonight at 7, in a game televised by ESPN.
"I think it's very important to remember but also very important to make sure it's not over-emphasized," Clemson coach Larry Shyatt said. "These teams have not met this year. We will have a chance, unlike in most leagues, to meet twice. This will be one of them, and hopefully we will do the very best we can."
The Tigers (10-6, 1-2 in the ACC) face a tall order. UNC (13-2, 3-0) is riding a 10-game winning streak and playing its best basketball of the season.
The Tar Heels dismantled Marquette 84-54 on Saturday in their last nonconference game of the year, holding the Golden Eagles to 29.5-percent shooting.
"Sometimes stepping out of conference play is difficult to do," UNC coach Matt Doherty said, "But I thought our kids really reacted and responded very well."
Doherty hopes his team makes a similar transition back to ACC play. He doesn't want to have to explain how Clemson finally got out of Chapel Hill with a win.
The streak is fun for fans of both schools, but it's nothing but a headache for Doherty.