Here are (a few) reasons people resist change so fiercely.
They Are Afraid of Change
They Don’t Know How To Change
They Don’t Know They Need To Change
People Around Them Encourage Them Not To Change
Change Is Hard
Not Taking Responsibility For Your Mistakes
Fear of Expectation
Some people fear that if they do successfully change their situation or their outlook they will be expected to perform at a much higher level. That higher level might require more effort and dedication than they are willing to give.