To actually get to the point where you do intend to carry out a full-stop landing, but put the wheels down, then open the throttles up and lift off again (unless you're flying a training flight which is supposed to be doing a 'touch and go') isn't that frequent.
Balking the landing at about 50-100ft isn't unusual.
It was this sort of incident which led to the Qantas overrun in BKK a few years ago:
"The aircraft landed long in a driving rainstorm after confusion between the Captain and First Officer on whether to go-around. The aircraft overran the runway coming to rest on the fairway of an adjacent golf course. Pilot error."
Basically, the First Officer (the pilot flying) responded to a go-around inititated by the Captain (the pilot not flying), but the aircraft actually touched down while initiating the go-around, and the Captain decided to change his mind and continue landing, retarding all the throttles, but not applying any reverse thrust. The aircraft aquaplaned on the wet runway, and ran off the end.
Despite heavy damage to the 747, Qantas had it repaired so they didn't record their first ever hull loss.
But, go-arounds of one sort or another happen several times a day at Heathrow. When there is a go-around, the Air Arrivals controller in the "cab" at the top of Heathrow's tower, will press a button which sounds an alarm at Terminal Control, West Drayton - where the radar approach controllers (the atc people who guides the arrivals to the approach) are located. The alarm serves to alert the controllers at West Drayton to the go-around - both so the approach controllers are aware an aircraft is coming back to them, and the departure controllers can ensure departures remain seperated from the go-around. I'm told that the sounding of the alarm can usually get a small cheer from the floor

.
I guess, in this situation, the crew may have seen some object on the runway that could have damaged the aircraft, and chose to go around, which is definitely the right thing to do! If there's any shadow of a doubt that it's unsafe to land, you go around!
Cheers!
Mike