Worth noting how :hover seems to reverse how you might intuit transition tags as working. If you want effects to have a different transition effect when being applied on hover than when going away once not hovering, the transition for it appearing has to go in the :hover portion. This makes sense when you think about it, but since when you don’t mind having both transitions the same the standard is to but the (opening) transition in the css line without :hover, it is easy to think you just have to add the new effect to the :hover, when you actually have to swap them.
This came up for me when I wanted dropdowns to be ‘bouncy’ on open ( all .9s cubic-bezier(, , , ); ), but linear on close (you can figure that one out :p).
The simplest transitions are coordinating conjunctions, also known as the "FAN BOYS" words: for, and, nor, but, or, yet, so. These common words help us connect not only our words but our ideas. For example, when you use the word "so," you are saying, "here's something that we can conclude from what I just said." When you use "or," you are saying, "here's another possibility." The most commonly used coordinating conjunction, "and," is also the weakest in terms of the meaning it conveys, indicating only that "here's something else." Coordinating conjunction do act as transitions, but they are not enough to give an essay a strong sense of cohesion.