The cat was frisky.
The cat was really frisky.
The cat was very frisky.
The cat was just frisky.
What do you write? These words are usually used in speaking, really, very and just. If you're writing first person, these words can be gold. However, if you use them too much, they clutter a reading experience.
Also, these words are free-to-use in dialog, especially because they are spoken word comments. If you use them right, they can add character in dialog.
Sometimes, you really want to say really. It adds something. My advice is to use these words sparingly and with intent.