Absolutely agree - people look ridiculous, and seem to just be "trying to impress" others?!? I can't imagine they are THAT important that they have to answer phone calls so quickly that they couldn't be bothered to take a telephone (or headset) out of their pocket before answering a call.
It also seems 'rude' to whoever they are with - as if whoever MAY call is more important than who they are currently with...