The screenshot is from Elixia’s application while booking a class. It’s a
nice app that gets the job done, but it also works as a glaring example for lacking context while doing an important action. Which class am I booking? Did I hit the right one?
In most cases the problem is more subtle. Little clues in the UI however can make a huge difference and make the user feel more at ease.
You could also question why do you need a confirmation dialog when booking a class but that’s a whole another story.