Worry is not an attribute to aspire to or admire.
Maybe that seems obvious, but here is why I'm voicing my option on the matter: A few short days ago I was conversing with a fellow designer who relayed a conversation he was apart of in which a developer suggested that designers can't/wont be good project leads because they aren't the worrying type.
Confused, I asked him to clarify what the developer meant by that statement. He proceeded to explain to me that this developer holds the opinion that designers are too carefree to be trusted with worrying about the level of detail a project lead is responsible to care for.
As a responsible, professional designer, I'm completely offended by that statement (on many levels).
First of all, that kind of blanket statement is generally made by the arrogant and naive – a disgusting combination.
Second, since when is worry a quality to be sought after? Worry is absolutely unproductive! Worry is a negative trait that should be avoided by mature, responsible people. (Which is not to say that mature, responsible people should not have concern for things, on the contrary.)
It's up to the individual developer and designer to nurture the necessary skills to be a project lead - both of which have predisposed strengths and weaknesses – both of which have proven to be excellent project leads.