[Avodah] A Gutte Yahr - A Good Year?

[Prof. Levine via Avodah]

It is customary at this time of year to wish others "A Gutte 
Yahr"  (A good year)  However,  aren't we supposed to believe that 
whatever Hashem does is for the good,  so no matter what will happen 
in the year to come,  it will be a good year.  (We may not see it 
this way,  but again whatever Hashem does is good.)

Thus,   I do not see any purpose in wishing others a "Good year."

Any explanations and or comments will be appreciated.

YL