Basic is good, advanced is even better.

You have to mix things up now and then.

A good bartender is hard to find. Learn the trade and you shall always have something to full back upon. The hours are bad, however, and you'd better have comfy shoes.   Also have a little philosophy at your fingertips!

Somewhat helpful, but methinks / You don't need it for decent drinks. / Mixology may seem tres genteel / But it all tastes good when you've got tequil. / No sweet ingredients can turn to swill / Though martinis need more skill. / Drinking with your minions / And spouting off your 'pinions / Should always together stay / Whether at your bar, or on RIA! Cheers!

Not for me, but I'm sure many people would find it enjoyable at least. As far as it being "useful", comparing it to skills which can save lives or greatly improve lives, it's not all that important.

I hardly ever drink. Never really saw the point of paying a lot of money for expensive liqour mixes that would only make me incompitent and sick for 12 hours.

Knowing the basics, at least you won't be embarrassed when the boss' wife asks for a cosmo.

As in mixing drinks, "mixing it up" in a social sense, or just being perenially confused?

You gotta be able to mix a decent drink here and there.