Nandi: The Symbol of Patience 

Whenever we visit to any of the Shiv temple so we see a sacred Bull which is sitting outside the ship temple question arises about it's significance. Why is it sitting outside of every temple? Why is it so important? 
It's basically termed as Nandi which is waiting in a delight for his God.
Nandi is not waiting for him to come out and say something. He is in waiting. Nandi is a symbolism of eternal waiting, because waiting is considered the greatest virtue in Indian culture. For instance, whenever we go for an interview or any of the major career oriented work we usually try to reach earlier and wait rather than being late. So from that way also waiting is considered as a great virtue.
One who knows how to simply sit and wait is naturally meditative. He'd got patience and peace. He's so much calm and compost. 
He is not expecting Shiva to come out tomorrow. Basically, it directs us to not to have any sort of expectations if you're in wait of anyone. It requires dedication and whole lot of patience. He will wait forever. 
Nandi is Shiva’s closest accomplice because he is the essence of receptivity. Before you go into a temple, you must have the quality of Nandi – to simply sit. Going to temple is another level thing which nowadays people don't understand. It's all about routine, devotion and perseverance. We usually misnorm meditation as seeking process rather it's simply listening process. We listen to our environment, our body, our brain and other numerous things which we usually forget in day to day life. 
So, at last we must know how to wait, how to be patient and seek what actually required.