Let me start with my No. 1 pet peeve in real estate: a "for sale" sign in front of a house with no information other than the Realtor’s phone number.
Now, I have heard a LOT of reasons as to why this is a preferable practice. Mostly, I think, these justifications come from a very selfish place in the heart of the Realtor. Here are the two most oft-heard — and hideous — excuses: