I'd find it difficult to say, "excuse me ... [etc]" without adding Sir or Madam.
I remember being earbashed by a female customer [She would've been late 20s/early 30s to my nearly 60], saying, "Don't call me Madam, I don't run a brothel; I'm not your Love, Darling or Honey/Hun; we're not on a building site, so don't say mate, pal or similar" to which I replied,
"how would you like me to address you?" to which she replied, "not at all"
So I guess that's it. I do find it hard, not to say anything else, after "Hello, Good Morning ..." Clearly my upbringing, schooling and 40+ years of dealing with the public. Milkman/DJ/Civil Servant/Journalist/Shop worker. I like to think I've always said it politely, not cringing, being sarcastic or ironic or smart-ar$ed.
I hope that doesn't sound pompous !