I don't make things grow, Yet I decide whether growth was worthwhile. What am I?

Three leaves I show in fields of green, but four brings luck rarely seen.

Sleek and playful, I love to glide, Down muddy banks, I slip and slide. Floating on water, I float on my back, Cracking open shellfish for a delicious snack. Holding hands with my friend so we don't drift away, I whisk through the rivers and spend time at play.

I am a warm, wet forest where it rains a lot. Tall trees, vines, monkeys, and colorful birds live in me. What am I?

I may pour drinks, throw strikes, or lure a fly, one sits on tables, one aims high. One waits in gardens, green and still, what am I, with more than one will?