why do people give cops a hard time?

If a cop is polite respectful and just doing their job then I tend not to take it personally even when it has consequences for me I am never happy about the situation but I do not hold it personally against the individual. The only time that I speak bad about a police officer is when you have a case of those that go up far and above the Call of Duty as it were and actually enjoy punishing people Beyond any need. For instance a detective that has such a hard-on for you that they will bend Or Break The Rules just to put a case on you and then while you are in jail not only drum up and manufacture more evidence whether true or not but go as far to separate you from friendships or destroy your personal relationship and even killing your dog. All because they're mad that you exposed to one of their family members as a snitch. Those people are not police officers they are bullies and criminals with patches there is a big difference