Perils of the code

For you IT types. Go here for the whole thing, which is supposed to be set to a tune I'm not familiar with, "Leslie Fish":

Deep in engineering down where mortals seldom go,
A manager and customer come looking for a show.
They pass amused among us, and they sign in on the log.
They've come to see our pony and they've come to see our dog.

. . .

From briefcase then there comes a list of things we must revise,
And all but four within the room are taken by surprise,
And all but four are thinking of their last job with remorse;
The customer, the manager, the doggie, and the horse. 

. . .

Three things are most perilous,
Connectors that corrode,
Unproven algorithms,
And self modifying code. 

The manager and customer are quick to leave this bunch,
They take the dog and pony and they all go out to lunch.
Now how will we revenge ourselves on those who raise our ire?
Write code that self destructs the day the warranties expire.