Where is Home?

It's kinda funny how I don't know where home is. Do you? Yeah I grew up most of my life in Michigan with my parents and my little brother. When I was there- MI was definitely home. But all the time I was there, I couldn't wait to get out to Cali. Now I am in Cali. Sometimes I go back to MI to visit family and friends. Michigan is definitely not home anymore. But California is not home either. Why is that? I have been out here [San Diego] for nearly 3 years. Is home a physical address, or is it something more than that? Home may be where your network of family and friends is located. In that case then MI would still be home, but like I already said- it doesn't seem that way when I go back. Maybe it's something else- maybe something else altogether. Maybe "home" is an idea. When I think back to the great times in MI with family and friends it was definitely home. But, did I call MI home when I was there? Like now- I can't seem to call Cali home- but when I look back on this in 5 years- San Diego was my home. Here is the entire list of the places I have lived since birth....

Santa Barbara, CA
Grand Rapids
Ann Arbor
Whitmore Lake
Canton
Ypsilanti
San Diego, CA

Where is home?