These are learning phenomena you describe. I'll try to explain a simple way to think about this.
By default, sweet foods are appetitive and, for instance, strongly bitter foods are aversive. However, it is possible to condition yourself to associate a stimulus, no matter how it presents originally, with a different valence (appetitive or aversive).
There are several well understood forms conditioning can take. I list a few here, and some subtypes. They are described well on Wikipedia:
Operant and classical conditioning are the two major paradigms to know. Classical or Pavlovian conditioning involves pairing an "unconditioned" stimulus with a neutral "conditioned" stimulus. Operant conditioning involves providing a feedback, usually a reward or punishment, to reinforce learning.
You can self-learn or condition yourself. This does not mean necessarily it is intentional or conscious on your part, often things can be subconscious or unconscious. For instance, if you associate eating crisps with watching a movie, watching movies without crisps can become uneasy, in spite of the fact that watching a movie was originally a pleasurable activity. In a neuroscience seminar involving conditioning in fruit flies, I once recorded a saying which captured the spirit of the experiment quite well: An expected reward, not experienced, can feel like a punishment, and vice versa. Rewarding yourself after doing chores can also be a easy and practicable way to build good habits with doing chores.