@Kooki - I totally agree, some agents are not trying really hard to sell the property and the vendor is being kept in the dark about everything that's going on.
However, some vendors PREFER to be kept in the dark, in fact - they insist. Get this: we're at inspection and viewing this house, right after the inspection we accidentally meet vendor's father and start chatting, he tells me what is the reason his daughter is selling the house and other interesting details and I asked him - can I call her directly, he said yes and gave me the number. Ideal, right? So I rang and spoke to the vendor and made my offer directly, and she promised to get back to me with an answer in a day or two.
Guess what - a minute later the agent rings and starts shouting at me "how dare I go over his head and ring the vendor". She rang him and asked him to deal with me, she turned down the offer on the spot and wasn't even going to consider it.
A few months later that house was sold for 20K less than what I offered. The end