You have a seven dog rule.
The walk around the park, if taken twice, is equal to a mile. And while you really do have a goal to walk more, you are getting really frustrated with all of the dog owners not picking up after their pets. As a result, you now have a rule that if you meet seven dogs on your walk, you quit. Even if you have not yet finished your mile, you call it quits.
It may seem like a pretty crazy guideline to follow, but the fact of the matter is that you have reached the conclusion that for every seven dog owners you see, at least one will not be carrying doggy waste bags. And you are an expert at looking for those doggy waste bags. You have made the mistake in the past