We've been all there. There is a specific type of disagreement that you just know it will go nowhere. It's an endless loop. Just back and forth with the same answer from both sides.
Picture this moment. You are working on an idea with a colleague, and then you say "the idea will work great as an app". But your colleague disagrees; "no, an app is a bad idea". It doesn't matter how long you go on; you'll find booth won't move from the same answer: pro and against the app idea.
Avoiding this nightmare, it's not about going for one or the other option. The solution is to look for another solution.
We tend to see ideas as if there were only two possibilities. Yes and no. But that's not true. There is a vast range of options out there. For example, going back to our app example, it would be better if our colleague says "I'm not convinced about the app, but what about a web app?".
The secret is always to take the idea to next phase. Take whatever is positive about it, and make it better, instead of just answering "no".
Next time your ideation session starts looking like a tennis game, look for alternatives and remember to contribute with something positive. Don't end up in a loop.