Keeping to topic, I usually just play a few instantly recognisable lines and then put the bass back down. People who don't play bass don't want to hear something technically great that they've never heard before. They want to hear The Chain, Money, that White Stripes song (yes I know its not a bass, but non-players swear it is), Peaches etc.
I may occasionaly fool around and do some Beat It, You Can't Touch This and I Want You Back but thats about it. Thats usually enough to satisfy people who struggle to believe you actually play the things.
In music shops, I just play the stuff I like playing, not really bothered if I sound crap (to others). I know how bad I am, I never claimed to be good.
And, as for the above - I think I'd rather listen to a drum solo than a bass solo, even with a looper. Never understood loopers. Why not get a band?