When an experience has meaning there is usually an emotional aspect to that experience that strengthens the connectivity between neurons making it easier for us to recall.
This makes sense from a biological perspective. Being able to remember a bad experience from the past helps us to avoid one in the future.
The disadvantage of this is that positive things can have negative connotations because of the way they were experienced. Think about your mother force feeding you vegetables when you were younger perhaps, or an encounter with an unfriendly dog that has led to a lifetime fear of animals for example.
The same is true of exercise of course. Many of the people I talk to about exercise can still recall the dreaded cross country runs of their school days, or the ritual humiliation of communal showers following PE lessons.
These memories have nothing to do with exercise but more to do with how it was presented, or enforced to be more accurate.
The sad thing is that once these associations are made they are difficult to break. In fact the associations become so strong you come to expect them. Most of you will have experienced a personal trainer shouting for one more repetition, or a boot camp instructor barking out orders in the park.
Exercise doesn’t have to be delivered in that form however and to do so is usually counterproductive both to your goals and to your long term health. These negative associations must be broken for the exercise experience to become the pleasure it should be.