By viewing countless homes with listing agents, assuming you as the buyer(s) aren't walking around with your mouths duct-taped shut, you risk divulging information which "could" be used against you should you decide to later purchase any of those homes. In Washington State, when you meet with the listing agent as a buyer, the listing agent is bound by a legal duty to the seller - unless you have a written "dual agency" agreement which states that the real estate agent is in fact representing both the seller and buyer (more on that another time). With this said, "legally speaking," the listing agent is required by the state licensing law to divulge to anyone viewing the home that they represent the seller. But in "real life" it is all too easy for this not to happen as it should, due to distractions or other countless situations.
By making a seemingly benign comment like, "Wow honey! - I just can't live without this kitchen - this is exactly what we're looking for!", you may have just raised the price you ultimately pay for that home, because the listing agent is obligated to inform the seller of your "excitement" since it could result in a higher selling price. (And, wouldn't you want your listing agent to do this for you as a seller?)
So, next weekend when you feel like walking through all those open houses, if you're thinking about making a purchase soon, be aware of your conversations - don't just "gab" with the agent who is present without thinking first! You don't have to be rude, and you can feel perfectly free to ask any questions you like... just don't be so free with the information in return.
Read more about buyer's agency, and the benefits of using a buyer's agent to purchase your next home!