Yes of course it does - but I've been to Barcelona many, many times and on every single visit (bar one) I've witnessed someone have their bag snatched right in front of me. (In London it's more pickpockets and mobile phone thefts - and I've already told the OP of a friend who got mugged near Harlesden a couple of days ago and mentioned that gun crime here is on the rise)

I just wanted to stress that the cleanliness of pensiones and the areas in which they are wasn't such an issue as it is in London (where the area you stay has a greater impact on the likelihood of your encountering crime).

You should take the same precautions everywhere as you would in New York, even Tokyo.