The problem with police officers is that what we want them to do is 10% of what they do. 90% of the time they are doing things we don't want them to do, like writing tickets, harassing good people, and jailing stoners.
Further, all the large scale crime happens with their consent.
There is no way that a semi-truck load of blow rolls into a large city every day without the police being in on it.
At the bottom of every large scale crime you will find the po-po.
Lastly, there are too many times when calling the cops is the worst thing you can do.
Imagine if your wife has gone insane and is attacking you, throwing thing at you and breaking everything in the house. Well, if you call the cops, in most states, the man will be removed from the house. (and the children will be left with her)
Also imagine your friend is ODing and having a bad trip... what do you do? Call the police and go to jail, or let your friend die?
Or call the police about a break in and be shot and killed.
50% of homicides aren't even investigated.