As a Celtics fan, I'll keep it a buck...
The chatter during, and immediately after, the WCF got to me a bit. I had some level of doubt.
But right before the Finals started, I thought about the matchups and how Dallas would match against Boston's starting 5 on both ends of the floor. Then, it hit me
... the matchups were deeply out of Dallas' favor. Limited weapons on offense outside of Luka/Kyrie, and playing 5v4 at maximum on defense. If Boston did what Minn didn't do and exploit tf out of Luka on defense, they could collapse the floor easily and kick out to anyone for 3. Thus, creating a shytload of open shots.
I ran this by the basketball guru at work and he straight up was like, "That's why Boston about to sweep
"
The only person I know who called the sweep for Boston prior to the Finals starting