I spent my formative years surrounded by people who had a distinctive way of speaking. My own accent was never particularly strong, but I knew folks who were incomprehensible to outsiders. I have a certain fondness for this way of speaking, even though it has certain negative associations.
So then I went away to grad school in a place where the locals had an equally distinctive accent (but distinct in a completely different way). I spent my first couple months inwardly giggling at everybody around me, but before I knew it, I had picked up this additional accent. At the same time, in some sort of subconscious rebellion against the new accent, my original accent got a lot stronger.
Now I have what has been called charitably a "lilt". I have ceased making fun of celebrities with odd or fake sounding accents (e.g. Madonna), because I sound sort of silly myself.