Cali?

What’s up with people calling California, “Cali”? It sounds very odd to me. Never heard it called that when I lived there. It’s funny, but I often hear it called that from people who think of themselves as Californian (maybe lived there for a few years). But I don’t think any natives would actually say Cali. SoCal sometimes, but not Cali. I don’t know… whatever! Nevermind me.