How I make simple, yet satisfying animations!
I'm no animation expert, but when animating my mushroom for my game Snail away, I tried to follow some animation principles:
Exaggeration: you can see the stretching of the mushroom being greatly exaggerated
Squash and stretch: the volume of the object should stay consistent, so when stretching one axis, the other axis should squash.

You can see how just using 3 keyframes, I was able to make a simple but very satisfying animation, adding quite a bit of game juice. Here's also how it looks in-game:
