Unhelpfully is the adverb of unhelpful: it describes doing something in a way that does not help, and often in a way that makes the situation a little worse. It has two quite different jobs. Most often it sits next to a verb and comments on how somebody acted or spoke: he unhelpfully suggested we start again from the beginning; the sign unhelpfully pointed in both directions. In these sentences the speaker is judging — usually with a dry, tired kind of humour. English speakers reach for this word when someone technically did respond, but the response was useless, or beside the point, or made more work for everybody. It is one of the classic quiet-complaint words, especially in British English, where it often carries a faint eye-roll. The second job is at the front of a sentence, where it comments on the whole situation rather than on one person: Unhelpfully, the shop had closed early. Here nobody is really being blamed — the world was just being inconvenient. One useful thing to notice is that unhelpfully rarely accuses anyone of being cruel. It says something fell short of being useful, not that it was cruel. That is why it works so well in polite, understated complaint: it is the mildest possible way to say that someone got in your way.

沒幫上忙地、反而添亂地。常帶一點無奈或吐槽的語氣，像中文說「不但沒幫上忙，還……」「很不上道地」。