What were the English thinking?

I overheard my dad explaining my 5 year old son how the scoring works in tennis. It was the US Open tournament and Belgian's Justine Henin was in the final. "Love" is "zero". You increase from "fifteen," to "thirty," and then (not forty-five, but) "forty". Then you switch between "deuce" and advantage". What were the English thinking? The scoring in soccer was so simple. Where did the scoring system used in tennis come from. I had to look it up.

Although the origin of "love" as a "zero" score is often heard of as representing the French word l'œuf (meaning 'egg') due to the similarity in shape between an egg and a zero, it is more plausible that it originated from the phrase 'to play for love' (of the game). The origins of the fifteen, thirty, forty scores are somewhat unclear - one common explanation is that the scoring system was copied from the game sphairistike, which was played by British officers in India during the 19th century. That game's scoring system was based on the different gun calibres of the British naval ships. When firing a salute, the ships first fired their 15-pound guns on the main deck, followed by the 30-pound guns of the middle deck, and finally by the 40-pound lower gun deck.

The scoring system is also sometimes said to have medieval and French roots. A clock face was used on court, with a quarter move of the hand to indicate a score of fifteen, thirty, and forty-five. When the hand moved to sixty, the game was over. Previously, tennis had a scoring system like table tennis or "ping pong". This explanation seems unlikely since Medieval France predates the advent of mechanical clocks, with sundials being the chronometer of choice at the time.

From: http://en.wikipedia.org/wiki/Tennis_score