It’s tempting with comparatives to focus merely on the form. After all, the rules aren’t that difficult to explain. But be careful not to oversimplify the use. For example, we often assume that comparatives are used only to compare two things.
I am taller than my brother.
But we can use it to compare more than two things.
I am taller than my brother and my sister.
We can also use the comparative without stating the other thing if it’s understood.
I feel better (than I did before).