A THOUGHT: I am sure that a whole bevy of people much smarter than I will ever be have made this point before, but it has always seemed to me that soccer, tennis, and pornography, three activities not usually mentioned in the same sentence or otherwise thought of as in some way linked, have at least this much in common: if you are not actually performing the activity in question, which is to say, if you’re just watching the balls go back and forth, the whole thing starts to get a little boring after five minutes or so. There does not appear to be a valid scientific explanation for this phenomenon in any scientific journal I have consulted, although there is a wealth of anecdotal evidence suggesting that this is in fact the case.