Getting too close for comfort
Unfortunately, while I enjoy being out with my lab on most days, there are a few occasions when I get frustrated by the actions of other dog owners who allow their dogs to run up to people and other dogs indiscriminately, sometimes even being aggressive. I always put my dog on lead, as this makes it easier for me to control him and it gives other people a sense of security. Unfortunately, not every dog owner shares my principle, so I cannot impose that we all put our dogs on a leash whenever we take them out for a walk. But for me, it is just common courtesy for dog owners who prefer to walk their dog without a leash to call on their dog when they do get too close to other people or dogs - for everyone's safety and peace of mind.
To leash or not to leash
We need to acknowledge the fact that, no matter how well trained our dog is, there will always be that possibility for a situation to happen which you have not trained him for, and sometimes the consequences could be quite devastating. So, before you decide to unleash your dog, remember the importance of leashes and how they give you greater control when meeting up with other dogs. You might be saying, "Don't worry, my dog is very friendly." Yes, that may be true. But what about the other dogs you meet? When in doubt, use a leash. It is always best to be safe than sorry.