Awkward silence can happen anywhere. No matter how adept you are at hiding your many social inadequacies behind a veneer of vaguely interesting conversation, that shit'll slap you in the face when you least expect it. I had one just the other day. I went to see a soccer match with some friends, and we met a guy who's a regular at the games. We struck up a perfectly nice conversation about many interesting soccerish things, like low scores and vuvuzelas. Then my friends popped off to grab a warm $12 beer and I was left alone with this strange potential hooligan. BOOM! Awkward silence descended, practically mid-sentence. We had plenty to talk about; we just couldn't do it. And so we spent the next five minutes fumbling for our phones to read pretend texts. I think I even did that weird thing where you fake a yawn just to fill the soundless void.
It's all about rejection. Conversations are surprisingly important for our mental well-being, and all it takes is a quick, awkward silence to take all of their benefits away and replace them with a heaping helping of "everyone hates me forever"-ness. Not just for the person who blurted out the awkward-ass remark that caused the lull, either; that shit applies to everyone in the conversation.
"See? Just remember that any break in conversation will wreck everyone's brain chemistry forever. No pressure."