Heck, don't worry so much, Dan, you were innocently talking to your cat. The lady on the sidewalk decided for herself that you meant her, and probably power-walked even harder, having been given an incentive (albeit in a mistaken way) to get herself fitter...

See, you did her a favour. :0) You were meant to talk to Mera, at that moment...and the lady was meant to hear you. Next time she walks past, she'll probably look like this:

Every cloud has a silver lining

;-)