A taste of the schmaltz-fueled good old days makes it nearly impossible to leave Sammy’s Roumanian Steakhouse without a smile. The mood at this raucous subterranean Lower East Side haunt is infectious, with live music and plenty of flowing booze — most notably bottles of Ketel One frozen into blocks of ice. Chopped chicken liver is given similarly lavish treatment, mixed tableside with caramelized onions and plenty of chicken fat. Of the entrées, none is better than the platter of garlicky skirt steak, a portion so voluminous that it hangs off the plate edge. Golden-brown potato latkes make a bold impression, each one the size of a landmine and packing a fitting quantity of explosive flavor. The victuals might be on the heavy side, but Israeli emcee Dani Lubnitzki keeps the mood light, teasing diners nightly with popular songs tweaked with Hebraic puns. (A bris is still a bris . . . It had to be Jew . . .) Every now and then, the room erupts into dance. Sammy’s is what happens when you mix neuroses and charoses — and a ton of vodka.