The thing that drives me nuts is when people start throwing out immediate ideas, sometimes before I've even given a full account of the problem. But even if they do wait, I don't feel like explaining why all your immediate ideas don't work - most of the time, I've also already thought of those things. Try asking questions instead.
Why don't you ask some questions about their obviously wrong solutions instead od spoiling the fun they have guessing? After all to are the one with a problem.
Please edit this so it says whatever you meant.