I hate being called sweetie by anyone I don't know. The same goes for honey or sugar or any other "cute" name. If I have never met you before, I'm certainly not your "sweetie." It drives me bonkers.
It bothers me slightly less if the person is elderly. I mean, they're set in their ways by this point in their life and they probably have grandchildren my age (and might have difficulty remembering my name). However, if it's someone my age or even into their 30s or even 40s, I want to reach out and slap them.
I realize that I am a cute girl. I look sweet and I'm really nice to you. That just means that I am fantastic at my job. I make you feel comfortable and you like me. However, once you call me "sweetie," it makes my job a whole lot harder and my blood pressure raises.
Even if I'm cute or sweet, I am still in a professional position and expect to be taken seriously. Would it be acceptable for me to call all of our tenants "honey"? I think not. So, why do people think it's okay to call me that? UGH! I just want to shake some people! You can be courteous and still be professional! Find the line, people!