Sparrows are one of the most overpopulating bird species on our planet. House sparrows, in particular, like to inhabit in urban and agricultural areas; in fact, they are the only bird species willing to dwell with human beings, thereby giving rise to various problems posed by such coexistence.
House sparrows basically love to feast on what we feast. They love to eat human discarded edibles other than seeds and grains. Hence, such eating preference has brought upon them antipathy from humans as a result of their annoying behavior of picking up leftover food waste from the garbage dumps outside of restaurants, residential houses, and the like. Many times we can even see these oscine finches hanging around the streets or collecting dead insects, moths and crumbs on the road that can only bring about inconveniencies on the drivers, plus, they always leave a mess on tar roads and around dumpsters. Notwithstanding their craving for insects and other pests which is advantageous to us households, the sparrows have, on the other hand, been categorized by us as pests themselves!
House sparrows can be the source of noise pollution too. These songbirds have the habit of chirping and singing their award-losing songs in the wee hours of morning when most of us are still sound asleep. Believe me, the chirping tune is vexatious to the extent that it can cause long-term migraine! All in all, the melody of a sparrow does nothing good except as a cost- and energy-saving natural alarm clock.
References:
http://www.humanesociety.org/animals/sparrows/tips/solving_problems_sparrows.html
http://ibc.lynxeds.com/photo/house-sparrow-passer-domesticus/two-males-moulting-non-breeding-plumage-female-bird-rear-water (image source)
http://10000birds.com/fighting-over-crumbs.htm (image source)