What term can describe feelings of discomfort due to unfriendly situations?

The correct term that describes feelings of discomfort due to unfriendly situations is "unpleasantly." This word captures the essence of experiences that evoke negative feelings, especially in the context of social interactions or environments that are not welcoming or friendly. When a situation is described as unpleasant, it conveys a sense of discomfort or aversion, aligning perfectly with the emotions being described.

The other choices do not maintain this specific connotation. "Aggressively" refers to forcefulness or hostility, which doesn't necessarily relate to feelings of discomfort unless in a very specific context. "Inconveniently" pertains to being troublesome or causing problems, but it does not directly indicate discomfort on an emotional or psychological level. "Irregularly" relates to something being inconsistent or not regular, which again does not touch on the feelings of discomfort associated with unfriendly situations.