I used to be pretty chill about picking up. I trusted pretty much everybody until I started having a reason not to. Nowdays I get pretty paranoid about getting busted and/or robbed and/or skimped even if it's from a reliable source. Always be on your toes.
Have to agree with what others have said, it seems that dealers have a different concept of time to the rest of us, 15-20 minutes tops, an hour later 8)
On the topic of dealers having no concept of time, I completely agree. I usually call my connects when I'm 5-10 blocks away and say, "I'm at your door, come out now." Then, 75% of the time I get there and still have to wait lol.
I think being nervous before a pickup just comes with the territory. I mean, you are doing something illegal. But it also depends how hot the block, dealer is, etc.