Well, it doesn´t have to be witty but I've come to the point that I usually log certain routine days without comments. Not that I´m training or racing much but I keep logging to motivate me to get my butt out the door - hopefully daily.
The wheels on the bike go round and round, round and round, round and round...
@bubo: It has to be witty. Always.
@feet: Have you spent too much time with small people?