The least productive teams I've been a part of are the ones where everyone is waiting for their turn to say why an idea is bad. Sometimes being "too smart" can hold you back from building something genuinely new.
There have been numerous times where I have identified real issues with an idea, advocated we crack on anyway and ended up with good results. Often you can't know for sure if an issue will even be that insurmountable until you get to it.
But there are other times where the risk/reward isn't lining up, or the risk is very well known, you've tried it before etc. Then hit the brakes, back to the drawing board for another try.
I think the danger is when people treat ideas as precious. In a well functioning team, your idea is going to get picked apart, modified, morphed and implemented by others. Get over your attachment to the idea as your baby, and you get to really enjoy the process.
Also many great innovations or discoveries have outlived extreme opposition. The problem isn't people saying no, the problem is having non-sociopathic people being reluctant hearing no.