Worms or Trojans?

I just wanted to know which is the Worst Type of Infection.

It really depends what they do…

They’re both horrible, but I’d say Trojan. :-\

Technically a worm can self-replicate and cause SEVERE damage, but Trojans are worse in a different way.
I would argue that worms are not as bad because they are usually easier to detect because they usually end up bogging down the computer and network.

Trojans pretend to be an application. They usually work flawlessly as well, maybe the application will run a little slower than average, but nothing that will cause average computer users concern.
The worst kind of Trojan is the downloader. In a matter of minutes it can fill your harddrive with worms, viruses, backdoors, keyloggers, and more trojans.
Also, a user, when prompted, will usually, obliviously, grant the trojan access to the internet, thinking that the application is perfectly safe.
Worms, on the other hand, run of their own will which may cause the user to question it. The Trojan runs when it is expected to- when the user clicks it. ;D