Do cell phone bars matter?

Readers, this is important! Okay, not important, important, but mildly important. Basically, it comes down to this: are cell phone bars even remotely accurate? I ask because there have been a number of times recently when I've had the envious "5 bars", the equivalent of a Unicorn riding a Pegasus. If I really have five-bar reception, why do I hear my mother say, "what's that?" and "I can't hear you". Does that sound like a mystical creature that doesn't exist? I thought not. All I ask is that you, the cell phone company, give me what I want: harsh and brutal criticism from my biological mother in real time. Is that too much to ask???