Same here, mostly because I've been a Mavs fan since the early 90s. I've witnessed the entirety of the Nowitzki era and the Three Js, and now Luka.
When people assume a certain team has all the advantages and going to curb stomp someone, it usually doesn't work out as they expect. I feel like Dallas is going to have a gameplan for the Celtics spacing and steal a few wins. It's not like they haven't seen a five-out offense before. OKC had one when Giddey sat.