When I was young and going through a rough patch with one friend or another, my mother always told me friendships go in waves. Sometimes you’re high on them, doing the most exciting things and seeing each other all the time. Sometimes it’s as though you don’t know each other (except you do, because you remember all the times that are past). I knew she was right, but when I was young I hadn’t had friends for long enough to see what she meant.

These days I’m not old, but I have friends who have been in my life for over 20 years and new ones who just arrived. Each friendship is different; the relationship components undulate as ocean waves do—always the same motion (hi…bye), never the same content (what is said and done, where and when we encounter). It’s only the movement, up and down, that’s constant over these relationships and across relationships.

When I think about friendships as waves, I envision the trendline as straight across with a sine wave tracing the points of each friendship. If you plot every friendship on the same graph, some will have wide peaks and dips, some will have steeper and more frequent slopes. But, regardless of the shape of each wave, when you follow the trendline as a representation of your life unfolding, you find that your time has been filled with moments shared with people you enjoy. Despite all the movement—especially the absences of certain individuals at certain times—you are surrounded by people you consider friends most of the time. In this way, the trendline makes you unshakable when one friendship wave becomes an outliner by dipping too low or dropping off the graph completely. And, also, it’s the trendline that helps you steady yourself if a friend becomes a partner and their friendship wave falls into phase (in sync) with your life wave magnifying your own emotional ups and downs.

For me, the visual of friends as waves (like an ocean view) takes a lot of the pressure off each moment because it makes me see them as part of something larger. It’s reassuring to realize that I can enjoy each crest before it crashes on the literal or metaphorical beach because it will be followed by others.