I'm tired of reading, "I'm so scared." Geesh, this is what it is all about. Without Game 7s, there is no reason to watch. Read Bill Russell's book, "Go Up for Glory;" he'll explain it to you in the chapter about Wilt Chamberlain.
Without Game 7s, the Celtics histroy is B-O-R-I-N-G and nobody would care.
As a competitor, this is what you play for. Bases loaded, 2 out, down 2 runs. 3 seconds to go, down 1, the ball in your hands for the championship.
Without Game 7s, the 1957 (first one) would not be as special. 1960, 1962(2 game 7s), 1963(conference), 1965(conf), and the ones I actually saw: 1966, 1968(conf, won games 5, 6 & 7), 1969 (I have on tape), 1973 (lost with Hondo injured), 1974, 1977 (lost), 1981 (best playoff series ever vs Sixers), 1982(lost), 1984 (vs Knicks, then vs Lakers), 1987 (There's a steal by Bird, over to DJ), 1988 ("That's what GREATNESS is all about" Bird vs 'Nique).
If you didn't experience any of this history, then be glad you have an opportunity today and a chance to see what could be a classic.
Game 7s are why we are the Celtics and they are not. 15-3 in deciding games. The only thing you should be feeling is anxiety to get the game started. Not scared.
Go CELTS! May the ghost of Red guide you to victory.