no they're not! they only appear to be friendly with tourists and especially with english speaking tourists (americans, british or kiwis...) 'cause you guys have a "tipping" policy that we don't in Europe since service charge is always included in our prices!
italian bartenders are freaking pirates! they'll always try to steal you in one way or another and they always manage to do so! by short pouring you or serving you a cheap vodka when you order a Grey Goose (for example); it's just that they've been doint it for so long that they've become masters at this stealing art!!!
trust me, I've worked with Italian bartenders for a long time now (I'm a bartender too) and I know 'cause they don't even hide it no more, amongts themselves, they laugh at how naive you guys are and how easy targets you can be....!