Actually here is a positive spin to add... The Celtics are very evenly matched with CLE, LAL, SAN, ORL... and a couple of these games easily could have gone the other way.
When predicting a winner, a person could say it is a 50-50 prospect, a coin flip.
Now if the coin flips against you 3 times in a row, do you then assume that your odds are dropping below the 50-50 split? No.
When the C's meet any of the other contenders in the finals, the coin tossing starts over. Anyone can walk away with 4 wins out of 7.
(of course if the C's have to win that toss on the road, it couldn't hurt to boost our chances with a little help for our bench).