But an inspection team from Estyn found some classes so exciting at Fairholme preparatory school, in the cathedral town of St Asaph, in Denbighshire, "that pupils continued discussion into their playtime".
The Fairholme report is the latest in the first series of independent school inspections to be published in Wales.
The team praised most aspects of educational life at the pound;3,660-a-year independent school, which has 88 pupils aged three to 11.
"Overall, standards of achievement are good and in some subjects outstanding," said the report.
"Children under five achieve outstanding standards in the areas of language, literacy and communication and in their mathematical development.
"Similarly, in key stages 1 and 2, pupils achieve outstanding standards in the core subjects of English, mathematics and science."
The children were advanced for their age, well-behaved and took pride in their work, said the inspectors. Teachers were also complimented for having a good knowledge of their subjects and high expectations of the pupils.
Fairholme was founded in 1900 and bought by the current owners, Mr and Mrs Cashman, in 1989. The couple, head and bursar respectively, do not disclose their first names to pupils or parents to maintain a formal relationship.
Their leadership and management was also praised in the report. But the inspectors found some shortcomings. Most pupils' skills in ICT were less well-developed and, in a minority of lessons, teaching was not stimulating enough. Elsewhere classes were criticised for "not always meeting the needs of every pupil".
There was a need to make better use of local history, and a lack of professional development opportunities for staff. The school's complaints procedure also fell short of the required standard, and the school must now write to the Assembly government explaining how it plans to rectify this.
Mrs Cashman said: "We know we have high standards, but to be acknowledged is very pleasing.
"We do have a complaints procedure. We just need to fit in with the common inspection framework that applies to state schools."
Regarding some lessons not meeting the needs of all pupils, she said: "A lot of schools teach the less-able but that drags down the class. When they come to us we stretch them and they can achieve."