“Try not to read my my mind, I am running five jokes in my head, that will possibly offend you and make you laugh. Another part of my head is accidentally reminiscing about college and now internally screaming. My lizard brain want food. And the rest is upholding this conversation.”
“First off, how did you block my mind scan, and secondly - lizard brain?”
“Oh a part of the human brain can be traced back to a reptilian ancestor thus it is dubbed the lizard brain. Speaking of lizards...” a green creature crawled out of the human sleeves. “Her name is Shelby.”
“That does not explain the mind scan.” -- Anon Guest
As a survival tactic, telepathy is not one of the more common evolutionary stepstones. Those who have it, of course, think it's vital until they eventual fact that other telepathic species are very rare and other cogniscents don't know how to do Private Thoughts.
That's when they learn to adapt to tuning out the seas of mental babble, or at least shutting themselves off from it until they consciously scan other minds. The Melil are experts at this, having learned their lessons and returned to teach those at home how to protect themselves before they encounter the harsh truth.
Of the telepathic species, the Melil are the most widely-spread because of their practical approach to non-telepathic encounters. Nevertheless, there are still some encounters that surprise even them. Like having a Human block them upon first greeting.