I was devastated when I saw I was being observed with my mixed ability Year 10 - the bane of my professional life. I briefed the class on the Monday that we would have a visitor on Wednesday and that I expected impeccable behaviour, politeness and a sprinkling of effort. Like the rest of my lesson, I could not be heard over the noise and drama that was the essence of my Year 10 lessons.

Wednesday approached and I thought the pupils were late until I realised they were lining up outside in near silence (a first all year and never seen again since). Pupils came in and stood behind their chairs, which was not even a school policy, and politely greeted our guest.

They wrote the learning objectives and eagerly put their pens down when finished. The lesson continued with the pupils not only being well behaved, but taking an active interest and answering questions when prompted.

I was amazed when I completed the lesson and read the feedback sheet. It showed me that you should not underestimate even your most difficult class - people are full of surprises. And sometimes if you ask for their help and support, they will want to give it. It was the first time I truly understood why I was teaching.

Worst: A few weeks into a teaching placement, I arrived to teach my Year 9 class only to find another class being led into the room by a supply teacher who had been told the room was available.

I had to find somewhere else for 34 pupils, some quite challenging characters and all getting excited at their nomadic status.

I eventually found a room that overlooked the fish pond at the entrance to school. However, my room with a view did not have the technology required for my lesson. My interactive starter was quickly abandoned and I was forced to think on the spot and improvise my lesson on 20th-century dictatorships.

I decided to try a little kinaesthetic learning and use the pupils to represent different people in a communist state. I explained the concept of equal wealth, drew diagrams and used coins from my own purse, but I could not hold their interest.

Two pupils were preoccupied with who could throw litter out of the window into the fish pond. As if this were not bad enough, the headteacher was on the bridge over the pond with journalists from the local press. To complete the nightmare, the boys understood my lecture on respecting our environment to mean that they should climb out of the window, dangling precariously over the water to pick out the milkshake bottle from the pond.

Thankfully the room was on the ground floor. I knew I should have insisted on keeping my original room.

Victoria Burns teaches at Hornby High School near Lancaster.