Opposite to what we think, "nice" actually had a negative meaning: "Middle English, foolish, from Old French, from Latin nescius, ignorant, from nescre, to be ignorant."
Here's the etymology of that schizophrenic word:
c.1290, "foolish, stupid, senseless," from O.Fr. nice "silly, foolish," from L. nescius "ignorant," lit. "not-knowing," from ne- "not" (see un-) + stem of scire "to know." "The sense development has been extraordinary, even for an adj." [Weekley] -- from "timid" (pre-1300); to "fussy, fastidious" (c.1380); to "dainty, delicate" (c.1405); to "precise, careful" (1500s, preserved in such terms as a nice distinction and nice and early); to "agreeable, delightful" (1769); to "kind, thoughtful" (1830). In 16c.-17c. it is often difficult to determine exactly what is meant when a writer uses this word. By 1926, it was pronounced "too great a favorite with the ladies, who have charmed out of it all its individuality and converted it into a mere diffuser of vague and mild agreeableness." [Fowler]
"I am sure," cried Catherine, "I did not mean to say anything wrong; but it is a nice book, and why should I not call it so?" "Very true," said Henry, "and this is a very nice day, and we are taking a very nice walk; and you are two very nice young ladies. Oh! It is a very nice word indeed! It does for everything." [Jane Austen, "Northanger Abbey"]
So the next time you say that someone or something is nice, be careful.