One thing about swimming a long way at the pool that's pretty funny is that some relatively fit guy will get in my lane, push the tempo, lap me once in eight laps then take a break as I go round, then pace me for a bit, then have a break as I go round, then disappear as I keep going round.
The anonymous and undeclared culture of "pool duels" has to crack you up, you can really feel it when the person in the next lane is thinking hard about exceeding you, because you so regularly pass and re-pass each other. There are some swimmers out there who are absurdly good as well, so there's no point getting cocky.