Serving The Lord is different to serving others. When we serve others with no thought for doing the Lord's Will, we may finish up in servitude to others' selfish demands. Answers to prayer come often while serving The Lord in His Way.
There is no such thing as an unanswered prayer, Gods answer is either Yes, my child. or its No, child I have something better for you. so when you dont get what you thought you were wanting just think, Gods plan is better for you. He wont lead you astray.
I don't believe that GOD ever tells us "no". He has three options, Yes, not right now, or I have something better in mind, Just be patient. The best collection of quotes and sayings for every situation in life.