I have one of those whistle things on my truck. Been on there for 17 years. Someone laughed and asked if it worked- I told them I guess so- never hit a deer. It's a two toned one, whatever that means.
I've been in a lot of great expensive neighborhoods that were ruined because of dogs barking without even hesitating. You can hear them near and far away.
Over the years I've come face to face with Rottweilers, Dobermans, Inu's, Pit Bulls, Ridgebacks, German Shepherds and so on. Careless owners forget to mention there's one in the back yard or in the house. The only thing that saved me was I didn't run or stare or allow them to surround me (had to change clothes a couple of times). But those little yappy annoying dogs don't care- they'll try and get you if they can before you can step on them.
I've left a house more than once because the owner of a Doberman (For example) was chomping at the bits and swore he was a good dog and wouldn't put him up.
Then you have the folks that just love their dog enough to chain it to a tree the rest of it's life.
Some people shouldn't have any right having a dog.
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