God created us in His image and He gave us the ability to express our feelings when faced with various life situations. We laugh and feel excitement and joy when something wonderful happens and we are sad when we're disappointed or faced with loss. Being sad doesn't mean that we don't trust God, it just means that we are expressing human emotions that God gave us when He created man. Many think that anger has no place in a christian's life, yet even Christ expressed anger while here on earth. Remember the corrupt money changers in the temple? It is not a sin to feel anger as this is a normal response to injustice. It's how we express and deal with anger that is most important. If anger is allowed to fester resentment in our hearts and rage out of control, then that's a huge problem as it destroys not only our own souls, but harms others as well. The best way to handle anger is to determine the cause, face it responsibly, and ask God to help control it. The Bible gives us wise advice in Psalms 4:4 “Don't sin by letting anger control you; think about it overnight and remain silent”. We can all enjoy victory in Jesus by giving God control over our hearts, lives and yes, even our anger.
Ephesians 4:26-27 KJV - Be ye angry, and sin not: let not the sun go down upon your wrath: Neither give place to the devil.
Romans 12:21 KJV - Be not overcome of evil, but overcome evil with good.
Proverbs 16:32 KJV - [He that is] slow to anger [is] better than the mighty; and he that ruleth his spirit than he that taketh a city.