But let’s say you instead ask them for a free slice of salami. Now they will probably think a free slice is no big deal, so they will hand it to you. Then you ask them for another slice, and another slice. Each time they will remember that offering a free slice is not a big deal. Eventually they will say no, but by then you have already gotten a chunk of free salami–more than if you asked for it all outright.
Salami tactics work by getting the other side to agree to small, trivial requests with the hidden agenda of getting them to agree to a much larger goal.