Rich people got rich people problem.
Many private home owners are assholes and make life difficult for each other.
Of cocurse there are HDB assholes too, but proportionately less. Can cham siong.
With the shoddy workmanship that is so common nowadays, apartment dwellers will eventually face all kinds of problems. However if you live on landed you are unlikely to have as many problems.
For apartment dwellers you have to worry about neighbours living above, below, left & right. If you live on landed you have fewer neighbours to deal with. There is usually a fence to keep them away. It's rare to have the problems like those experienced by the Everitt Neighbourhood

For those who think they have bad neighbours, things could be worse if you had neighbours like them http://eresources.nlb.gov.sg/infopedia/articles/SIP_441_2005-02-02.html