I was leaving work when I saw a lady in her sixties coming in the other direction just past the entrance. We made eye contact and as we did she put a banana skin down in the flower bed. I then said to her "it's not nice to litter".
At this point, she came right up to me and started an angry tirade that she was planning to pick up the skin on her way out, that there were no bins nearby and that I should not be accusing someone older than myself but addressing the younger generation instead. I quietly replied I would if I saw them do the same and got into my car and left a bit shaken by the encounter feeling like I'd done something wrong. Should I just keep my mouth shut in future?