Villains are always causing havoc for someone.
Heroes and civilians alike are always under the looming threat that some ill-intentioned person in an outlandish costume is going to turn up at their place of work, the bank or even the supermarket and ruin their day. Imagine that you were out buying eggs and you ended up having them stepped on by Stilt-Man on the way back to your car - it's not on.
Some villains are egotistical and they'll announce their plans before they strike, either by broadcasting them on the TV or the internet. Either way you'll know what to expect, but some villains fail so much that they eventually retire... or end up on the wrong end of The Punisher.
Arguably the most dangerous villains of all are the ones that are currently unaccounted for. These villains were dangerous, they were formidable and suddenly they went missing, so what are they doing and where are they hiding?
Not to be underestimated, there is always a chance these unseen and unregulated rogues could make a comeback.