The differential of a Druid is the versatile with many different forms. All druid can use bear, aquatic, cat, travel and flight form. Balance druids can use Moonkin, and resto druids can use treeform. Aquatic form is great for quest in water, because you don´t have to breath and you swim faster.
I have some great moment when I leveled as feral and was cat dps in groups. When the group was about to wipe, I could go out from catform use my group heal or another heal if needed. Change to bearform take aggro away from the healer and save the group. sometimes I have had to battleress the tank to.
In pvp I often use some mana to heal then when the mana are low I switch to bear or cat, then back to healing again, this stop you from getting bored.
As a tree I seldom switch out of form in a party or raid, only sometimes to take away poison or hibernate mobs
Some players start with one class get bored change to another and so on. Thats not happening when you are a druid. If you get bored you just change talents and you are a complet new player with different abilities than before.