De mortuis nihil nisi bonum.

De mortuis nihil nisi bonum.

concering - the dead - nothing - if not, except - good

L nisi < ne 'not' + si 'if'.

Nisi mecum concubueris, phobistae vicerint, “If you won't sleep with me, the terrorists will have won.”

Nisi mecum concubueris, phobistae vicerint.

Nescio quod curabas ... "I didn't know you cared" ...

Boy, them Latin phrase books sure do come in handy!

After posting the last one it dawned on me that English "caring about something/somebody" was a false friend of Latin curo 'to care or nourish'. Unfortunately, the only other verbs that now come to mind are all of 'em feelthy. Ah, well, it's been a long time since I took Latin, but Henricus Barbatus does have a goodly franchise there.

Best one of the lot from Lingua Latina Occasionibus Omnibus, for mine:

Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam!

Dear Capfka: I partcularly admire your ability to hold your catapault in one hand,hidden under your coat!

Bardocucullus ingens est. (? taking a flyer.)

Bardocucullus ingens est.

Cujus? Henrici aut Gullielmi medici?

Non medici, sed medica? Modo si *Medici, nec Henrici neque Gullielm; probabilitur Leonardo!

This is getting too hard! Fainites!