I have a friend that compares these experiences of love, joy, peace, etc. to appreciation of music. Especially of more challenging pieces, such as classical music.
For example, two people can appreciate a symphony by Mozart. The first, a novice to classical music, can whistle the melody and intuitively knows that it is quality musicianship. The second, a seasoned musician who has put years into her craft, can pick out the complexity, depth, and subtlety of every measure. Both individuals can enjoy and appreciate the experience of the symphony, but they are at different levels. Using your word, you could say the second person has "expanded" in knowledge and appreciation of music.
The nice thing about this is that you never "arrive!" There is always more to expand into, as love is infinite!
well put @abishai we all see things through the prism of our own making...individual perception is an ever expanding spectrum of knowing now what we didn't know then...when spread over the entire population. The fact that we all see the same thing just a little differently is one of the things we all have in common
~may all hatred cease...let there be peace~