Agree...Jason Terry was lost in space in Boston. I waited to see any sign of his vaunted shooting touch, and it never showed, along with terrible defense.
I think you probably only watched road games. Terry had extreme home-road splits both that year and the year before (in Dallas).
On the road (39 games) Terry shot a mediocre 31.3% 3PT% for a sub-par scoring efficiency of 50.2% and a lame 8.7 points per game on 26 mpg.
but ...
In The Garden, (40 games) Terry shot 42.7% 3PT% for a fantastic scoring efficiency of 62.5% and a decent 11.5 points per game on 27 mpg.
Pretty much jeckle & hyde.
That 2012-13
team had pretty extreme home-road splits, going 27-13 in the garden but struggling to just 14-27 on the road. Terry's shooting splits probably helped contribute to that.