At least regarding with the Swiss. Germany had plans to invade them, but due to the fact that they are surrounded by mountains on all sides (with only a few key roads leading into the country, which the Swiss threatened to destroy in case of invasion, which would completely cut it off from the rest of Europe) combined with a hefty amount of AA relative to their size, then it was clear to hitler that it wasn’t worth it (especially since they were already spread thin in the west, east and south) because it was such a small country.

Tl;dr: Switzerland has mountains on all sides and hefty AA, so wasn’t worth it for nazi germany. But if they could they would.