I am the last person to be mean to someone when they're doing their job. I know that sometimes at work you have to say no to people, you have to give them bad news, you have to be less than co-operative because of company policy and so on. I understand these things because I've had to work under those conditions and I know that the last thing you need when your hands are tied is some dick who yelling at you because they think that's how to get you to risk your job to get them what they want.
So I make an effort to understand when people's hands are tied, that sometimes doing a job means doing things you might not want to.
Then there are cold calling scams. Thanks to the wonderful resource that is who-called-me.co.uk I can generally know with some certainty whether an unknown number is a scam or not and so I take out my many frustrations on them.
I started off small time just asking questions they couldn't answer like when the accident I never had was, what the registration number of the car I don't own is, what bank or phone company they're representing and waiting for them to give up.
Then I got a bit bored with reason and started having fun. Once I had confirmation a number was a scam I'd answer pretending to be the police, pretending to be a hairdresser, answer entirely in German swear words (which include “Kevin”, for some reason).
Yesterday, I just gave up. I cued up a Youtube video of screaming and just put my phone next to the speaker. According to my phone, the cold caller listened to thirty-eight seconds of screaming before hanging up.
You might call this petty and it is but I don't get to be cruel to the deserving that often.