Agree to Disagree

A couple of days ago, we had an altercation at the pool where I exercise.  I was in the current channel, which is an oval area where the water is chest deep, and there are jets that propel the water in one direction around the oval.  We can walk either with the current, or against the current for extra resistance.  There are classes, where an instructor tells us what to do (forward, backward, sideways, knees high, skipping, and many more variations of movement around the oval. 
One of the instructors has been out for knee surgery, and the coverage of her classes has been sketchy.  So a number of us were there for a class, and there was no instructor.  No big deal.  We knew what to do, so we proceeded to do the various exercises, each in our own pace and order.  A woman on Oxygen got into the current channel towards the end of the hour, with a companion, who walked behind her, holding the Oxygen tank up above the water.  I wasn't sure how safe that was, but I was thinking of going over to her and commending her for continuing to exercise, despite her need for Oxygen.
A couple of the other people were doing stretches, standing along the wall, as we always do at the end of the classes. This woman went up to each one of the people along the wall, and told them they should not be there, that this area was for water walking, and if they wanted to do other exercises, they should go elsewhere. Neither of the two women she said this to stood up to her, I think they were too flabbergasted (I love that word).  I went over to her, and told her that usually there was a class at this time, and that the instructor had not shown up, so we were doing the class without her, and what these women were doing was part of what we do in class.  The woman with the Oxygen loudly and sarcastically stated, "I know what they do in those classes, but there is no class.  They shouldn't be doing this here."  I tried to point out that this was class time, and these were class exercises, but she continued to loudly state her case, that these people were in the way of people who wanted to walk in the channel (they weren't, there was room to go around them), and they were going to cause someone to fall (only if the other person wasn't watching where they were going, in which case, they, themselves , causd the fall).
I walked away, as did the others in the class who were there.  We could see very clearly that she was not going to listen to anyone else.  It was not worth my breath to try to talk reason to her.  In my mind, I agreed to disagree with her, and dropped the subject  Other than thinking about writing this blog, I did not spend much time thinking about this incident.  There are all kinds of disagreeable people out there, as well as agreeable people with whom I (or you) will disagree.  Give the situation the attention it deserves.  In this case, not much.  No one was harmed, and by letting people or incidents like this get to you, you are giving them more power than they really have.
The expression 'agree to disagree' is very useful.  It can come in handy in situations like this, as well as when the person or situation does matter.  We do this all the time, such as my friend who is a Democrat married to a Republican, or another friend who has 2 children, one who went to Ohio State, the other to Michigan (long time rival universities).  Agreeing to disagree is also useful when one person says "But I told you yesterday....", and the other person says "No, you didn't".  If two people view a situation differently, or remember it differently, in most cases one won't convince the other.  Rather than fighting, just agree to disagree.  Unless it is a vitally important decision, it seldom matters if everyone agrees.
If you are living with chronic pain or chronic illness, you likely don't have extra energy to waste on disagreements that don't really matter.  Some people like to argue.  If that is you, then picking fights with others who like to argue can be a form of entertainment.  I don't want to waste my time or energy this way, so be aware that if you try to get into an argument with me, I won't take the bait.