Connotation can be positive, negative or neutral. Choosing the right shade of meaning for a word ensures accuracy in speech and writing. Even so, depending on the particular social or cultural context, the connotative meaning of a word can change.
Synonyms for "house" might include apartment, mansion, castle, shack, hovel and condominium. Each word is a type of house, but each leaves a different picture in your mind. The word "home" explicitly means a building in which people live, but it also has positive associations with it, such as warmth, safety and family.
When you choose a synonym of a neutral word, it is important to determine the shade of meaning that you want to convey and the connotation of the word you choose to ensure they match. For example, someone who hasn’t eaten in three days is not just "hungry," he is likely "famished."