It was not just youngsters setting a bad example, adults drinking alcohol and smoking in front of their children were also a concern, Sarah Nation said.
"We were surrounded by adults boozing and chain smoking around their wee children and babies, spitting and littering, at the end of the night the family in front of us left all of their rubbish, beer bottles, smoke butts etc behind - what terrible role models some adults are to our children."
Police spokeswoman Kris McGehan confirmed they had dealt with, "some incidents" on Saturday, but could not elaborate on the nature of those.
Other concert-goers raised different issues, saying headline act Daniel Bedingfield failed to deliver and, at one point asked the crowd "have you ever felt so bad you didn't want to live?"
"I think someone forgot to tell him this was a family event and a celebration, not about self-reflection," Jane Reed said.
"We were just sitting there like 'you have got to be kidding me!'."
Even the arrival of Santa Claus failed to lift people's spirits with comments that he looked unenthusiastic and lacked authenticity.
Organisers were not fazed by the negative feedback, adding a few minor incidents were to be expected when running such a large-scale operation.
"I think anything where you are putting more than 100 people in one area in public you are going to get some things like that, let alone 25,000 people," David Trim, of the Kaisen Charitable Trust, said. "There would not be an event anywhere else where they have less problems."
He did not expect any issues to arise from a debrief meeting with police later in the week.
There was plenty of praise for Christmas at the Park, too - local cover acts and carols were popular additions, while a fireworks display that capped off the night was the highlight.
"On a positive note we loved the entertainment and appreciate all of the volunteer time put in by others to give all of us a great night free of charge, and wow, the fireworks were fantastic," Ms Nation said.
"My kids had a great time and we will go back next year."