Admit it. We don't know how to listen really. It's a common thing. When someone comes to tell us something, while we are listening, we already think what to answer. It's an automatic mechanism inside of us, and it usually leads to a lot of prejudges and misunderstandings.
In creativity, this is a complex problem. If you colleague tells you an idea, and while you are listening, you are thinking "Uhm that's bad" or "It's not going to work", you are not seeing its full potential or trying to improve it. You are just judging it. Good teams know how to get the best of each others' ideas, building on top of each of them.
Avoiding this problem requires a constant effort, but when you start, everything comes easier, we promise.
The easiest thing to do is, first, be aware of it. When your colleague is explaining an idea, try to stop judging it and continue listening. Wait until the end to ask questions or start making an opinion about it.
Remind yourself: the importance should be on the idea and the goal of the project itself. It's not about saying something smart. It's about actively listening and creating together.