The term "Modal operators" might sound weird. This refers to your mode of operating. They are words like must, should, can't, have to, mustn't, can, will and indicate possibility or necessity. There is a big difference between doing something because you feel you have to and because you want to.
We often feel we have to do particular things and have no choice. Words such as should, must, have to, need. Operators of necessity can create stressful states that are self-imposed and can be disenabling. We seldom really question whether we have to do certain activities or feel a certain way. We don't examine the real consequences of not doing things. This is probably more obvious when you hear other people use these words in a context you wouldn't.
States of necessity drive us to complete deadlines. For example, we might stay up all night to finish an assignment. This Meta model pattern can be useful, focus all our resources and help us get important goals. Many find it motivating. There is big difference between "I'd like to make an extra $5,000 this month" and "I have to make an extra $5,000 this month".
We often talk about things as though they are not possible to achieve or do. Our unconscious accepts these as limitations. These are words such as can't, it's impossible.
I can't find a new partner.
It's impossible to talk to her.
I can't get up that early to exercise.
What would happen if you could?