Some verbs are not generally used in progressive forms. They are called stative because they refer to states (e.g. experiences, conditions) rather than to actions. In a sentence like:
She loves/loved her baby more than anything in the world loves (or loved) describes a state over which the mother has no control: it is an involuntary feeling. We could not use the progressive forms (is/was loving) here.
Dynamic verbs, on the other hand, usually refer to actions which are deliberate or voluntary (I'm making a cake) or they refer to changing situations (He's growing old), that is, to activities, etc., which have a beginning and an end. Dynamic verbs can be used in progressive as well as simple forms. Compare the following:
Progressive forms simple forms
1 Dynamic verbs with progressive and simple forms: I'm looking at you I often look at you I'm listening to music I often listen to music
2 Verbs which are nearly always stative (simple forms only):
/ see you
I hear music [> 11.13]
3 Verbs that have dynamic or stative uses: