Awkward silence, is it a real experience or is it just an idiom handed down by the dead (non-thinking) and insecure?

There are two women in my work place, every so often in meetings and conversation they mention this in regard to customer interactions. I stay silent and do not know what the fuck they are talking about.

There is nothing awkward about it. I ask a question here, respond there, if the customer is not chatty and a two or three inquiries do not get them talking I tend to lay off. I find that being pushy and trying to force verbal interaction to be actually pretty awkward.

I will occasionally comment on the progress of the transaction, cracked a little joke here and there or something along those lines, but I might remain silent for several minutes while I concentrate on doing the work in an efficient manner.

These notions are like a cancer. One had the gall to yell across the store in my stead to get their information to pull up their account once. I quietly said, "You want to talk about awkward, that was awkward. Do not do that again." I thought afterwards that I should have added that she did know the whole situation I discovered upon greeting them and that she made a blind assumption, but I have since determined that would have been wasted effort.