Earth goes very well with Water. Earth needs water to 'unblock' them and Water needs Earth to help ground them and stabilize them. It does create mud though and can get both natives stuck unless there are nice aspects to help keep things moving.
Fire and Water can be problematic. But I am a Scorpio married to an Aries and it works well. He has a water grand trine so it balances out.
Fire/Water makes steam so it can be passionate and hot. But it also can create simmering anger and resentment..
Air/Water can be incompatible because the energy does not complement each other. It is not that air is 'unemotional' exactly. But it is a different kind of emotion than water and they don't show their emotions in the same visible way. Air signs can be very sensitive but they process things in a logical, rational, mental way and may come across as cold. But the pain or emotion is still real but can silently, invisibly released up into the ethers...