Aren't observations and opinions the same thing? Here's the definition of "observation" from dictionary.com...notice the synonyms:

Main Entry:observationPart of Speech:nounDefinition:comment on something scrutinizedSynonyms:annotation, catch phrase, comeback, commentary, crack*, finding, mention, mouthful, note, obiter dictum, opinion, pronouncement, reflection, remark, say so, saying, thought, utterance, wisecrack