My 12 year old son's church league basketball team just got fairly trounced; although both teams missed way more shots than they made.  As his team exited the court I noticed one kid openly sobbing, although I did not see him get hurt.  His mother immediately ran up to him, and as she held him proclaimed that the other team was playing "really dirty."  She then went on to comment on the lack of officiating, etc..  Now to me it looked like a bunch of kids mostly just having fun, this was a pretty non-competitive league after all.  I asked my wife if she saw any "dirty" playing- nope.  We both had no idea what this mother was talking about.

My wife and I are both professional coaches with several decades of experience between us, and we have seen a lot of "bad" officiating, coaching, and especially side line parenting.  We have witnessed the worst come out in otherwise seemingly nice people.  Youth athletics can be a sometimes toxic mix of ego, adrenaline, and parental protectiveness.  The thing is, overbearing, overly protective, and overtly hostile parents seldom produce the best athletes.  I wish I had statistical data on to support this, but I can say subjectively these kids may have a great season or two, but seldom make it to where the parents think they will end up athletically: almost never.  They burn out, rebel, or simply loose interest much to their parents dismay.

Officials make bad calls.  Coaches make bad choices.  And there are players that are simply better than the rest.  But this is part of sport, and shielding your kids from these things, or making excuses for them, makes your child less resilient, less adaptable, and most importantly prevents them from learning from their mistakes.  They become "hot house flower" athletes only able to grow if the conditions are perfect.  They fold under adversity and make excuses for their failures.  As they age and their environment becomes progressively less insular they cannot function as well as their peers.  

The first thing to internalize is that your child will learn much, much, much more from their failures than successes.  It is often hard for a parent to even use the word "failure" when it comes to their child, but failure, or lack of success if you will, is without a doubt the best teacher as it instantly identifies what needs to be focused on.  It tells your child what to practice, and how to get better.  If you miss a shot you can either lament it or practice it 100x and improve.  It is that simple.  Don't shield your child from mistakes; help them learn from them, or better yet help them to identify the mistakes.  Ask them questions- don't tell (lecture) them what they did wrong.  An athlete that has the introspection and objectivity to analyze their own game is an athlete that gets better.   

Because there is almost always an overly vociferous parent at every game, I think an important conversation to have is how to react to and accept bad calls as part of the game.  A child's perception is that the ref is out to "get" their team and likes their opponent better.  This is often reinforced by their parents.  It demonizes the refs that are often doing their job for the love of the game.  Point out that when one team is criticizing the ref., the other is usually congratulating their call.  The referee stands in the middle because coaches and parents are too subjective to make these calls; and this is a tough job!  They are also human and humans make mistakes.  What is important is that you do not let a call you don't agree with affect your game.  You may also want to point out that a loud mouth athlete draws more attention to themselves and may more likely draw a foul as a result.  And I believe you should have your child thank the ref after every game.

Parents should never criticize the coach in front of their child.  This breeds a lack of respect for their coach and undermines them.  The child may loose confidence in their coach and it creates another easy excuse for their own mistakes.  It is one thing if you doubt the competency of your child's coach, but it is another if you find that their character does not align with your own.  Coaches are very influential to a child and you must ask yourself, even if the coach is highly successful, if you want them to develop good character or become a good athlete.  Hopefully you have a coach that supports both.

As your child gets older progressively put more responsibility on them for their own success in sport.  If they want to get better they must work hard and practice; which means putting down the game controller.  If they are not getting enough play time, make them ask the coach what they need to practice on to get on the field more.  Most coaches respect this, and will take more interest in a child that genuinely wants to work hard and get better.  And if they are disappointed in their game have a discussion about how much they are practicing on their own; without their parent or coach telling them to.  The objective is to create an internal work ethic, not a child that practices when their parent nags them.  It is tantamount that they understand that hard work and practice equals progress.

Having a bit of separation from your child's sport is in my opinion one of the keys to developing a strong athlete.  This does not mean that you are not supporting them enough.  Protecting them from adversity is protecting them from learning and progressing.  There are so many positive life lessons and values to be learned through sport- it is a microcosm of life.  An important question to ask yourself is how much of your own validation is tied to your child through sport.  And if yourself musing on scholarships and athletic "careers" when your child is under the age of 12 let me just point out that very, very, very few kids are even playing the same sport when they graduate high school much less being offered a full ride, but every kid needs to learn character and values.