A fagaletti is one who is
annoying, frustrating and acts like a real dickhead....the
person described knows they are being a real pain in the
arse.....
Person in the office is going around getting right in peoples faces being generally
annoying, telling jokes that are not particularly
funny and has really bad breath, from the previous night of eating a garlic
based spaghetti....therefore that makes this person a fagaletti.
Or
Your driving along quietly and a person that has been riding up your arse for the last 10 minutes zooms past....as he passes you yell in an opera voice 'Fagaletti!'