The damage that unresolved issues can cause...

*Taking from an article on dealing with healthy & unhealthy anger:

When Expressing Anger Crosses the Line

Anger is a powerful emotion that can be a healthy expression of strong feelings that result in a constructive outcome. When anger is felt too intensely, too frequently, or is expressed inappropriately it can damage important relationships and create a cycle of conflict for the individual experiencing anger's emotional control.

When anger is associated with negative consequences, such as violence, road rage, verbal abuse, threats, physical damage (broken objects) repeated interpersonal conflicts, or anger-related health problems (e.g., exacerbated ulcer, headaches, muscle tension) it is no longer a healthy expression. If angry outbursts are affecting your family, friends or coworkers, then it is time to consider more appropriate responses to prevent damaging relationships or doing something you may regret. There is no clear boundary differentiating "normal" anger from problem anger. However, if how you express anger bothers you (or should bother you), gets you into trouble, or is damaging relationships, it may be time to consider getting help with anger management.

Men and women may express anger differently. For instance, anger is more socially acceptable in males, and is often expressed physically through fighting. Women are more likely to talk about their feelings of anger and problem-solve with others. Relationships can be difficult from time to time. People disappoint one another, say and do hurtful things, and can be hard to get along with. Identifying a problem in your relationship while it is occurring can be complicated because relationship dissatisfaction is experienced differently by those involved in the relationship. It goes without saying that certain actions, like violating a law or a code of honor generally upsets most people. Many individuals can easily work through minor differences, but sometimes a series of minor issues can build up over time and become a relationship issue. 

Here are some important relationship facts:

• People who are in romantic relationships tend to be happier than those who are single.¹
• Difficulties getting along with a boss or coworkers can impact work performance.
• Couples experiencing marital problems tend to be less nurturing and their children are more likely to exhibit behavioral and emotional problems.²
• Regular healthy social contact can be a buffer for depression.
• Important relationships can be good sources of support when experiencing positive or negative life events.
• Distressed couples experience a number of negative emotions such as anger and jealousy, or psychiatric problems such as depression and anxiety.²

Interpersonal, physical, sexual, or emotional abuse is a clear sign of a relationship in trouble. There are many types of relationships that exists, and it's always important to acknowledge these signs before they reach their breaking point, thus damaging important relationships that have long-term-meaningful potential.