And then there are others who have lived it.
Here's today's history lesson: Not including this year, 25 NBA Finals have been tied 2-2 after four games. Of those 25 series, 19 were won by the team that emerged victorious from Game 5. So historically, the numbers are on the Celtics' side.
But in this case, history is something that Doc Rivers knows all too well.
The last team to win Game 5, go up 3-2 and lose the Finals? The 1994 New York Knicks.
The Knicks beat the Houston Rockets at home 91-84 in Game 5 of the '94 Finals, then they headed back to Houston and dropped Games 6 and 7. Rivers was watching from the Knicks' bench.
He had begun the season as the starting point guard in New York, but a knee injury he suffered in December kept him out of commission for the year. The Knicks made a midseason trade for Derek Harper to replace Rivers in the starting lineup, and so the future Celtics coach watched, helplessly, as Harper, Patrick Ewing and John Starks collapsed in the final two games of the '94 postseason.
"I just thought about that the other day," Rivers said Sunday night after his Celtics beat the Lakers in Game 5. "John Starks called me and reminded me of that."
It was Starks, the Knicks' explosive, trash-talking shooting guard, who coughed up his team's shot at a championship. He got his shot blocked at the buzzer by Hakeem Olajuwon to lose Game 6 by a score of 86-84, and he shot a devastating 2-of-18 in Game 7, missing all 11 of his 3-point attempts. The Rockets won Game 7 in their building 90-84 and sewed up the championship.
"We had opportunities, obviously, in Games 6 and 7," said Rivers. "You know, that's a bitter memory, obviously, for me. I was injured sitting on the bench, you know, so you just felt like you couldn't help individually. As a team, we had a lot of great opportunities in that series, in Games 6 and 7 if you remember. But it just didn't happen."
Rivers never did win a championship ring as an NBA player. In fact, he never played a minute in the Finals — he made one Eastern Conference finals appearance with the Knicks in 1993 and came off the bench in '95 for a San Antonio Spurs team that made the West finals.
The closest he ever came to a ring in his playing career was watching from the bench.
"It was obviously a learning experience," he said. "But I can't use that experience for the players on this team. Hell, half of them are too young to remember, and half of them probably don't care."
But still, you have to figure the experience can't hurt.
Because of his past, Rivers knows that you can't take anything for granted with a 3-2 lead. Especially not on the road, and especially not when you're up against one of the game's great winners. Whether it's Hakeem Olajuwon or Kobe Bryant, the song remains the same. You've got to fight to the bitter end.
The Celtics have to view Game 6 in Los Angeles as the biggest game of their season. They have to play like there's no tomorrow.
"Yeah, you do," said Rivers. "Bottom line is when they won Game 3, from that point on, we felt every next game is a must game. Each game is Game 7. We said it in Game 4, we said it again [in Game 5], and we'll say it again. That's how we have to approach the game. We lost our wiggle room by losing [Game 3]. The Lakers played well enough to have home‑court advantage all year, and so it's to their advantage."
Those that don't know their history are doomed to repeat it.
But Doc Rivers lived his history, and he refuses to let it happen again.