It’s funny that I took the parent comment as referring to programming languages, but it totally works for people learning spoken/written languages as well. It really is a universal thing.
with respect to those particular questions:
many more people speak spanish than italian due to colonial-age history, and portuguese is almost a spanish dialect. for us residents with culinary aspirations, it may be worthwhile to know that spanish is required for most us restaurant kitchens. but italian isn't that far from spanish either; learning either spanish or italian will make it much easier to learn the other
ancient greek or biblical hebrew depends on which books you want to read. the torah is in biblical hebrew; platon, the hellenistic scientists, and the new testament are in classical to koine greek. modern hebrew will help you a lot with biblical hebrew, because it sort of skipped 1800 years of the sort of linguistic mutation that transformed classical latin into spanish and italian, and it is of course mandatory for living in israel. it may be helpful for flirting with israeli backpackers too