This is the anti-pattern where people making compromises to, mainly, business stakeholders in order to get things accepted. Unfortunately this leads to a bloating of the programme and a lack of clarity in its goals.
The causes for this tend to be political intransigence and gaming. Someone will object in order to get their own pet project on the agenda, a political game will then ensue leading to the person getting their pet project in order to support the overall programme, this will be repeated over and over again leading to multiple pet projects being added to the cost, and timescales, of the overall programme.
A good example of this sort of anti-pattern is the US Congress where "pork" is regularly attached to bills in order to get certain senators or congressmen to vote in favour. The recent $700bn bailout bill for instance had a huge amount of added pork what this means of course is that things get more expensive than originally budgeted and become more complex to administer (more cost again). It also means in delivery projects that there becomes a lack of focus on the key goals of the programme and instead there becomes a focus on getting the pet projects done well to keep "Person X" happy.
Rapidly the programme descends into a fractured mess as the pet project sponsors care only about those elements and not at all about the over all objectives. Team members realising that success can be achieved via a pet project delivery also focus on those areas as its a more immediate return. The overall clarity of the project is lost and it loses direction and ultimately fails.
The first part of the resolution is making sure you have a very high level sponsor who can drive over pet projects. To do this you need a clear, and concise, vision that a senior exec will sign off on and then you need to be clear in what does, and what doesn't, drive you towards that objective. The next bit is getting a backbone. Its very easy to give in and put a pet project in, its harder to stand up and say "no, it doesn't fit here" and the key to that is firstly doing it privately making clear your objections and then secondly doing it to the overall sponsor and finally that sponsor then doing it publicly. Rapidly people will stop trying to force in the pork if they find themselves accountable for trying to push it in.
The final bit is about culture, you need to establish a culture of "do one thing well" that focuses people around simple clear objectives and makes any pork pushing attempt ridiculously visible. The more concise your vision and objectives the harder it is for the pork to be added.