I've lived most of my life in New England, and some of the things I appreciate are:
-the variety of seasons
-fall foliage colors (and the nice weather that time of year)
-snowstorms in winter that allow for some good snowshoeing
-lots of trees--when I go somewhere (like visiting my relatives in Montana) that doesn't have as many it feels weird!
-nice outdoor swimming in the summer--especially here 15 miles from the ocean--I can have my pick of going to the beach or one of the local lakes
-the fact that the hot summer weather doesn't go on for TOO long...
-having some hills rather than just boring flatness
-hiking/camping in the White Mountains

What I like better about Maine then Massachusetts:
-closer to good hiking/outdoor activities
-not really a nature thing, but LESS TRAFFIC and better drivers!!! Less crowded in general.