Every stakeholder has an opinion. So they should. But if every stakeholder is pushing and pulling the design of a product in a different direction - even if every stakeholder has some knowledge of design, and every stakeholder won't - the result will function poorly and please no one. Like users, stakeholders will tell you what they think they want with little idea of what is actually needed. If you can make them understand that their knowledge of engineering or sales or contracts does not qualify them as art directors or graphic designers - and the good ones will know this already - then you will be able to proceed more efficiently. Beyond the subject matter experts, your colleagues - managers, artists, programmers - will likely have views that they will feel should be accepted gratefully and integrated into the design. Compromising here - to keep the peace in the office or out of friendship - will compromise the design.
Management will often announce an initiative to promote collaboration. Sometimes they'll rearrange the workspace to serve this goal, without realizing the effect an "open" or "collaborative" workspace can have on getting the actual work done - distractions and interruptions can become the rule rather than the exception. In that case you'll find yourself looking for ways to get the work done despite all the collaboration. Don't take this to mean that good ideas cannot come from anyone, anywhere. But you have to retain the power to pick and choose. If you're designing the product, be sure you make the decisions. Individuals decide. Groups decide to meet again.