Many business owners, have little to no technical knowledge.
Many programmers, have little to no business experience/understanding (especially if working for a project that may not particularly interest them).
Successful companies, usually have people who are the exception to this rule under both cases (or someone to bridge the gap).
Otherwise, well you end up with 100,000 threads moaning about "programmers don't deliver what i want" vs. "clients don't know what they want!"
Some programmers are happy to just do EXACTLY as told; which is a problem. "You didn't tell me the site has to scale and support a million visitors a day, so I didn't bother indexing my DB fields".
Other programmers, go to the other extreme and are perfectionists, not understanding that time=money (not just in their compensation, but in the "get-to-market" sooner = money). For example, in some companies, launching a new feature that will have a 25% impact two weeks sooner, by taking acceptable short-cuts (risk of minor bugs) could equal 6 or 7 figures extra revenue.
As for the clients, it all starts with them often not understanding their own technical needs. The programmer, before typing a word, should communicate and get everything laid-out and agreed upon. Obviously, not for free, as that can be a time-consuming process. He should also be pro-active and make suggestions the client may not think of.
Lack of communication and lack of experience in the other's field IMO, are the cause of most complaints. Followed simply by people with no work ethic, heh.
