Pro-tip for writers,

because I’ve been seeing this a lot. 

To be is the most common of the linking verbs and also the most overused, but all the linking verbs invite generalization and distance. To feel, to seem, to look, to appear, to experience, to express, to show, to demonstrate, to convey, to display – all these suggest in fiction that the character is being acted upon or observed by someone rather than doing something. She felt happy/sad/amused/mortified does not convince us. We want to see her and to infer her emotion for ourselves. He very clearly conveyed his displeasure. It isn’t clear to us. How did he convey it? To whom?

Most linking verbs have active as well as effectively passive forms, and it is important to distinguish them. She felt sad is effectively passive, but she felt his forehead is an action. If the magician appeared, he is acting; but if he appeared annoyed, then the verb is a linking verb and the only action implied is that of the observer who perceives this. 

Linking verbs, like the passive voice, can appropriately convey a sense of passivity or helplessness when that is the desired effect. 

From Writing Fiction: A Guide to Narrative Craft by Janet Burroway