Error Messages

I typed up a few error messages, until I stopped at this one, and thought about what style would appeal to most users.
I'm sure there's a standard on writing error messages out there...

"Cannot delete storage unit because it either has samples in it, or components associated with it. Please fix the problem and try again."
OR
"We're sorry. The storage unit cannot be deleted because it either has samples in it, or associated components. Please empty the unit or delete the levels and try again."
OR
"Cannot delete storage unit."
OR
"Are you stupid or what? How can you delete a freezer if it has samples in it? Like... honestly!"
OR
"A little birdie has informed us that you are attempting to delete a storage unit. If you do not want to be infected by a deadly virus on your computer, loose your front teeth and be constipated until the next full-moon please do not try this again."
OR
"Danger. Do not delete storage unit."
OR
"This operation can only be performed by an expert. You are not an expert. And this should not be tried @ home."
OR
"javax.12342345345CONSTRAINT.exception We terribly apologise for this incovenience, but we really can't let you delete this storage unit because of foreign key constraints. Error code 23505."

The possibilities are endless. Comments?