Neighbors

My neighbors downstairs are constantly banging on the ceiling, purportedly to complain about my noise level. Though occasionally their complaint is warranted (I can think of only twice in 4 years when I felt I was being overly noisy (once being last night)), often they bang on the ceiling when I'm not making ANY noise at all. Often they bang on the ceiling literally within the first five steps I take into apartment upon coming home from work and I'm SURE I'm not making that much noise to warrant complaint, maybe a bit of floor creaking at most. A few weekends ago I was sitting on my couch, with NO music or TV on just working on my computer and they started banging. I definitely wasn't making ANY noise at that point, so I had NO idea what the deal was. I don't want to be a bad neighbor and feel legitimately bad that I was overly loud pretty late last night, but also think they could lighten up a little. I don't know any of my neighbors at all and couldn't pick them out of a line up if pressed, but still I feel bad being a nuisance to others. I guess from now on I'll just have to try harder to keep it down. I've been meaning to get rugs to cover the hardwood floors for some time now, maybe that will cushion the noise a bit and bring peace.