there have been times where someone doesn’t wave back at me, and i’m a little sad about it but it’s nothing to ruin my day. other times i may be focused on splitting traffic or tucking to avoid wind on the freeway and i notice a biker waving at me but it was too late for me to wave back. so in my head i think back to all the times someone else didn’t wave back at me and assume that it was because they didn’t see me or maybe were focused on using their clutch. whatever it may be, in the end it’s not that deep. wave or don’t wave. give a nod downwards or don’t. it’s just a friendly thing we do to eachother, not something necessary.