Sometimes less is more. When you're running a MongoDB aggregation in your Spring Boot app and you don't want to return every field, use the project operation.
Because sometimes just one choice isn't enough, you need to allow users to select multiple options. That's when you include a multiselect dropdown on your form.
In some online forms, you might need users to enter a phone number. Wouldn't it be great if your Angular application formatted that phone number on the fly?