I can't comment on Slavic false friends but I've found that for French-English, Spanish-English and French-Spanish, if you really force yourself into thinking the words in the correct accent, the "friendliness" disappears. As the two words are pronounced differently they are thought of as their own concepts, instead of related to each other. Say "Journey" vs "Journée", if pronounced correctly they don't sound anything similar at all. We should remember words as they are spoken with a strong accent. Maybe for false friends it would be even better to exaggerate the accent.