One of the most important philosophical virtues is humility: the drive to reconstruct your opponent's argument in its most convincing form and to limit your own claims to that which your arguments strictly prove. Philosophy without humility is mere rhetoric. And there's a kind of philosophical humility that is very useful in everyday conversation, even for non-philosophers. It ties into the philosophical definition of knowledge as justified true belief - in short, A knows that p if and only if:
1) A believes that p.
2) A is justified in believing that p.
3) p is true
where A is a person and p is a proposition. Here's what I'm calling epistemic humility: respect for another person's justifications; for the second component of truth.
Often we meet steps 1 and 2 but fail at step 3, which is another way of saying that many reasonable-sounding propositions that are supported by evidence turn out to be false. This holds for scientific propositions (Ptolemy's cosmology, for instance), mathematical propositions and philosophical propositions. It's usually impossible to know whether a certain philosophical proposition is true until you've gone down the route of justification. A common and unfortunate pattern of behaviour is believing that steps 1 and 3 are all that matters - that if you believe in something that turns out to be true, you're 'better at knowledge' than somebody who justifiably believes something false.
Let's take anarchism as an example. Say you're studying the ethical implications of anarchism - concepts of freedom, property, coercion and all that - and, while you started out fairly anarchist-leaning, you end up after several years at a middle-of-the-road establishment leftist position. In this instance, you were wrong - and the legions of commenters at places like Balloon Juice were right. "You took your time coming round," they might sneer, "but I always knew you hadn't really thought your position through." But this kind of thing is coming from a person who has not thought their own position through themselves! Are they really 'better at knowledge' than you?
This is where epistemic humility comes in. What the establishment leftists ought to do here is recognize that you had justification for your anarchist position, just as they and the far-righters have justification for theirs. Unless you're holding a position that's obviously wrong (few positions fall into this category, especially if they've been written on by philosophers at some point or other), you deserve at least an appreciation of why you hold that position.
Be humble in this sense, and don't ridicule people who took a long time to come around to your position. After all, they know that their old position was wrong, while - even if it's true - you just believe it.
(I should mention that the example above is purely hypothetical, and I am still a dyed-in-the-wool bomb-throwing goatee-wearing anarchist. Smash the state, yo.)