Nobody knows everything. There are even some things which no one knows.
If somebody asks a hard question at the Saloon, it's OK to guess at an answer. But please, please, let them know when you're guessing. Don't say, "Just delete all your gorms, then reboot," unless you're sure that's the solution. Say "I'm just guessing here, but have you tried smarming the framistat?" Or "I'm not sure, but I think it has something to do with boontling."
If somebody asks an easy question, don't guess at all: wait for somebody who knows the answer to come along. You don't want to confuse a greenhorn with wrong answers.