The new Halloween takes place 40 years after the original film and sees that Jamie Lee Curtis’ Laurie Strode has never truly gotten over the events of the original film.
As Karen eventually rebelled against her mother and has become somewhat estranged, it makes sense that Karen just doesn’t enjoy Halloween the way most of us do.
One assumes that the anniversary of the attack on Laurie was never an easy time in the Strode household.
She has trained herself to fight in case Michael Myers ever comes back and she has also trained her daughter Karen to do the same, something Karen never truly accepted.