Some verbs describe states and feelings rather than actions, so they are not used in progressive tenses.
Admit, agree, be, believe, belong, care, consist, contain, depend, doubt, envy, exist, fit, forget, hate, have, hear, hope, imagine, involve, know, like, look like, love, matter, mean, need, own, possess, prefer, promise, realize, recognize, remember, seem, suppose, suspect, understand, want, wish.