If you have all kinds of contacts on your iPhone or iPad, ranging from friends and family, to significant others, to business partners and bosses, then you have a responsibility to take extra care to ensure your messages never go to the wrong person.
Helping to prevent sending messages that are intended specifically for certain people to the wrong person is a new free jailbreak tweak called MessageFilter by Frozen Penguin. It works by allowing you to set up a special blacklist and whitelist system to manage where certain kinds of messages are allowed to be sent.