Can an "opinion" be right or wrong?

a view or judgement formed about something, not necessarily based on fact or knowledge.

(Oxford Dictionaries)

This basically says that it is based on personal belief (i.e. "personal opinion") so can it be "right" or "wrong"? Or is it based on the content/phrasing of the opinion? For example,

I like Vanilla, and I dislike Chocolate

vs.

Chocolate is the worst flavour, Vanilla is the best

Solution 1:

I actually do think that opinions can be wrong. Consider the following

In my opinion, the Earth is flat

In my opinion, Saddam Hussein had weapons of mass destruction.

You can call these 'opinions', but they're factually wrong.

Solution 2:

I like Vanilla, and I dislike Chocolate,

Those are statements of fact. You cannot argue with someone if they say they like something. The most you can do is accuse them of lying.

Chocolate is the worst flavour, Vanilla is the best.

Those are someone's opinion. Different people may have different opinions about what is the best flavour.

Note

Someone has pointed out that I hadn't specifically answered the question. Looking back at my answer I see that I missed something. "X is the best" is not a fact - it is an opinion - Why? Because it is not sufficiently defined to be a fact. We can ask "According to whom?".

Answer

So, in my view, a fact is at least in theory verifiable or falsifiable. An opinion is insufficiently defined to be verified or denied. For that reason it cannot be considered right or wrong.