Doing a touch and go from a glide approach is always one to watch out for if you forget to re-trim and gives a good lesson in what can happen if you take off with the trim too far back.
You will already have the trim setting quite far back to maintain the glide speed, and when your on the runway and have added full power, the nose tends to rise quite quickly compared to "normal" and at a lower speed, causing you to actually have to push forward on the controls to get the nose back down to a more appropriate attitude to allow you to climb away without stalling, and requiring a rapid nose down re-trim to easy the control forces which can be quite substantial on some types.
Ask your instructor to demonstrate on your next flight.
