Did you announce yourself? If so, a decent-distance in advance?

I can't count the number of times that people announce themselves just as I can see them in the corner of my eye. By then, it's too late.

If in this case you wouldn't have been heard if you used voice, getting a bell would be useful. I'm often riding "in my own world" on MUPs and when I hear a bell it brings me back. Voice will scare the crap out of me (my fault) and I jump a little---hopefully not swerving too much.