I love my portrait lenses but one of my favorites is my Canon 85mm 1.8.
This particular portrait lens allows you to do close-ups with details such as in this picture with Miss Daisy resting.
This lens can isolate the subject while allowing a shallow depth of field. Basically allowing the background to be creamy and out of focus.
If you love photography and do not have a portrait lens do your self a favor and get you one.