The smoke billows across the back fence and you have to go inside and shut the windows.
That neighbour is at it again. If you're lucky it is a bit of paper and cardboard that should have been recycled but chances are an acrid smell tells you that the rubbish includes plastic.
Heat, plus plastic and other materials sets off chemical reactions leading to products that irritate the nose, eyes and skin. The plastics may contain chlorine as well as some more complicated additives, so the results of the burn can be an unpredictable brew including known carcinogens such as dioxins.
Throw some treated timber off-cuts into the mix and the neighbourhood may now be getting arsenic, formaldehyde and other serious pollutants added into the smoke. It probably won't kill you but that is an extra exposure that you didn't ask for and which is certainly not good for the lungs and other organs.
Then there is the true fire-lover who nurtures their smouldering fire regularly with weeds all day, and day after day. The wetness of the plants means great volumes of damp smoke, forcing the neighbours into the category of passive smokers with all the health impacts that entails.