>I'd venture to say that except for ransomware today's viruses and trojans are more discrete and do less harm to the user because if the user notices them he's

>I'd venture to say that except for ransomware today's viruses and trojans are more discrete and do less harm to the user because if the user notices them he's going to take action to remove them and that weakens the botnet or the ad delivery collective system which seem to be what viruses and trojan writers really want to have. You're right, that certainly is the goal, but IME almost never achieved. I've cleaned up quite a few infections and almost all of them have caused some kind of system instability or another. Virus writers have surprisingly shoddy programming skills.