On any project you eventually reach some sort of sticking point. As project manager, you see the need to go one way and the project stakeholders will want to go another. Once, at such an inflection point I was actually told, “Let’s go our way. You guys are smart. You’ll figure it out.” The pressure to give in and give in and make everyone happy is huge. You don’t want to disappoint and negatively impact your career. Don’t give in. You will do more harm in your career in not delivering than by sticking to your guns.
Knowing when to stick to your guns is something that you have to learn by experience, meaning that you have to get it wrong a couple of times before you get a feel for how to get it right, but when you know you are right stick to your guns.
This doesn’t mean confrontational meetings that result in either sullen silence or “Take it or leave it” declarations. It does mean politely holding your ground. A good resource for how to do this is the book Crucial Conversations: Tools for Talking When the Stakes are High