Part of the struggle of an immigrant to fit in any society is mastering the language.
You might be good in grammar and have a decent accent, but until you integrate some of the street slang, you are doomed to get singled out as a foreigner. Ulpan schooling is not always fit for the need of the new immigrant, as it teaches standard Hebrew, which is not your best bet at the macholet (neighborhood grocery store).
The Lonely Planet’s Hebrew phrasebook includes an useful table of idioms on page 28-29, but some of them are already out of fashion, borderline ridiculous (I have been told). Slang is something which evolves: like fashion collections, expressions which were “in” last year, might be totally “out” this year. For instance, the phrasebook lists the expression “tered li me ha karakhat” (lit. get off my boldness) as a means to get rid of a nudnik, but my friends laughed at this idiom since no one has been using since at least… mmmh…. the 90s.
A language is not only words, but also stock phrases and sounds which sneak in between words and make your sentence alive. I am talking about the various “mh” “eh” “ah” sounds, which Italian do a certain way and Israelis do differently. Just think of the little word “dai”: Italians use it as an incitement (=come on! emphatic), Israelis use it as basta, enough, stop it. A fellow blogger has written a gorgeous post called Guide to Monosyllabic Hebrew. Because I am late to work, and because I have to cook for 20 people for the Christmas dinner tomorrow night, I’ll direct you to this precious little web page which will help you be (or at least sound) more Israeli.
ps. the guide is more funny if you actually, like me, are struggling to learn Hebrew