I've been on both sides of this when living in apartments in the city.

In one place, my downstairs neighbor was oversensitive. I seldom wear shoes at home, but she insisted I was pounding around the place. I would be reading, she would claim to hear me making noise. She would bang on her ceiling with a broom in the middle of the night, waking me up. Nothing was moving in my apartment as my cat was asleep beside me. I had no idea what she was hearing, but it was not me. But she would not believe it and would keep banging. We talked, she seemed nice, but then the banging would start up again. I got tired of it and became less caring. I considered taking up tap dancing (but didn't -- although on at least one occasion after an unjustified banging, I improvised a bit.) Fortunately, I had a change of job and moved away, relishing the thought that the landlord would be doing a lot of renovation in order to be able to increase the rent, and she would find out soon what noise upstairs really was. I remain sure that there could be no living tenants much quieter than myself.

In the same place, I had a series of upstairs neighbors. One set tapped into my cable TV cord, ruining my picture. They disengaged their link when I requested it (and mentioned that it could be a crime.) Another set of tenants were starting up a punk rock band which practiced in the apartment above, loudly and, to my mind, rather horribly, at any hour. They also had a lot of friends who buzzed all the other tenants to try to get in (possibly because their pals couldn't hear the buzzer over their music.) The punk band was a bit hard to take; the amps produced not only noise but vibrations strong enough to knock pictures off my walls. They didn't last long, fortunately. Most other upstairs tenants produced a normal amount of noise/minor irritations, nothing to write about. Nothing to really complain about. I expect to hear neighbor noise as we both are carrying out our lives living in an apartment. People do talk, and walk around and watch TV, and sometimes have parties or fights or sex in their homes. People like to exercise and play music and sing to themselves. Some of this is unpleasant to hear, but mostly it is a part of living in close proximity to others. In the city, there are also traffic noises and ambulances passing and busses and trucks, maybe the subway sounds can be heard. The everpresent din. I learned to live with that, too, even when it drowned out all conversation. One must learn to accept what is around one, or change where one is.

I like peace and happily left the big city. I now live in a little house in a semisuburban village. My two cats are pretty quiet, as they sleep a lot. Sometimes they knock something down or chase each other. They might be elephants running in my house then. It's amazing how loud an 8 pound cat can be. The clock ticks. Sometimes a faucet drips. There are neighbor noises, and dogs and cars and motorcycles. There is a lot of bird noise in the morning and cicadas and frogs at night. There is the sound of rain hitting the tin roof on the porch of the house next door. There is the sound of water dripping from my own gutters. There are day sounds of lawns being mowed and hedges being trimmed; in the winter, snowblowers and shovels scrape away the snow. People use power tools. I can hear the fire station sounds blocks away when an alarm is raised. The garbage trucks ride around. The school busses pick up sleepy kids at an early hour (often serving as my alarm clock) and drop them off later, wide awake and energetic. The kids play and run and scream and act up; they ride skateboards. People call out to each other and chat across the road. These are all expected noises and unavoidable. These are noises of life. I don't even want to avoid them.

I don't know if LW is overly sensitive, or if the noise is actually horrendous. But there will be some noise wherever one lives. Perhaps a monastery in which silence is strictly observed might be quiet, but even monks walk around and rosaries clack and sandals slap against stone. And I am sure that some monks slurp their soup. Perhaps at the top of a mountain in Tibet it is utterly quiet-- aside from the howling of the winds. Perhaps in the desert? But what about the sand sliding down a dune? How much quiet do you need, LW?

As a landlord, I would not consider noise to be adequate grounds for breaking a lease unless the tenant at least discussed the issue with me. I have no idea what causes thumps at 3 a.m. It might be fixed easily.

Finding a tenant takes time. It costs me one or two months rent every time someone moves out. Only once have I had a tenant ask to leave after a brief stay, and while I agreed to let him go - an unhappy tenant is worse than no tenant - I charged him for the privilege.

... I had inadvertently created a problem which generated noise. Another cat, a 20 lb plus male Maine Coon Cat, did not accept my aging spayed female's presence on his turf. Cat fights are not pleasant to listen to; I worried it was disturbing the neighbors, and I was also worried he might hurt her. I couldn't even tell where he lived, he appeared to come up a trail that divides homes facing different streets. But he calmed down and now provides me when a source of entertainment, as most alpha males do.

The happy sounds of life, laughing and singing, are a lot more tolerable than those which reflect discontent and dissatisfaction, specifically arguing and bickering. In my second place in LA, there was a Korean couple who argued a lot and threw things at each other in the next building. Though I don't speak Korean, it was easy to tell what they were quarreling about. A fair number of calls from the neighborhood to the police were for domestic disputes. But you can get that anywhere. I don't miss the regular whirring of the LAPD choppers overhead, but when I lived there they quickly became a background noise. You do have to harmonize with a lot of the noise that is part and parcel of high-density living.