I've been riding my bike pretty much every day. Traffic is increasing and many folks are out walking their dogs, taking walks, and riding their bikes. I've seen a concerning occurrence on multiple occasions and that is folks who are their bikes passing walkers, joggers, other bicyclists and dog walkers failing to call their pass. If are riding your bike and you don't call your pass in a split second multiple folks can be injured. A dog walker can let their dog move to the left, or a walker can decide to cross the street or another bicyclist may move to the left quickly to avoid a pot hole or eaten away asphalt.
It is really not difficult to say alert the person(s) that you are coming up on that you are "on the left" or "passing" or "behind you". Also, remember do not call your pass when you are already up to the person because you may startle them and cause an accident. Call your pass when you are 10 yards or so behind. It is courteous and will allow folks to stay safe.