This comment has really stood out for me (From 60 Years of Challenge's book when discussing Approach Apathy)

This is why guys can be in total silent on a car ride for an hour, and then suddenly start talking.

While its perfectly acceptable to not always be talking, if its Friday night and you are out at the bar, you probably went out to socialize!

This is why "warm up sets" (or really just being social with groups of ppl near you) is so important!

Also, I personally have noticed that getting in a social mood with PEOPLE YOU DON'T KNOW THAT WELL (or at all) is a separate beast altogether. You can feel like conversing with friends all night, but never branch out. Or, you can start innocuous conversations early and often with anyone so that you build social momentum to talk to a cute girl when the moment arises.