Sometimes I find myself saying "should." As in, "I should drink more water," or "I should exercise." Phrases like these are almost always followed by a mental "but I don't want to, so I won't or I don't." The should introduces self-judgement and scorn. The later mental note brings indulgence. The two together cause guilt, a highly praised nasty emotion that starts an emotional debt we often don't repay or forgive.
Guilt is something we want other people to feel when we feel wronged. Something about someone saying "I feel so bad about that..." settles some sort of emotional exchange in us when they are blamed for our own discomfort. In this case it is ourselves who are the wronger and the wronged. Guilt makes us feel better and worse here.
Fortunately, debts can be settled one of two ways. They can be repaid or they can be forgiven. Luckily, you both own and owe this debt and can choose either way to resolve it.
So the next time you find yourself saying "should," catch yourself and deal with these emotions up front. Why "should" you? What are your other options? If you think this is something needed, why don't you do this? If you can answer these questions truthfully, you will eventually come to a decision on what you are going to do from now on. It could mean putting exercise on hold for awhile or starting right away. Whatever you decide, enjoy it as much as you can and your wants and needs will align more and more.
"Should-ing" yourself causes a mess that only you can clean up and no one else can really know about. Although sometimes (in extreme cases) it is a necessary removal of waste, and makes you feel better. Sounds a lot like sh***ing yourself...
Not a counselor, but just my $.02