Other things, sometimes you can get away with something that just advances the plot, or just characterizes. But set-up and foreshadowing are particularly hard to do. Oh, yes, this is going to be important later -- and there is no suspense about whether it's going to be important later.
Yes, you have to show the gun in Act One to fire it in Act Three. But dumping it in the middle of Act I is clumsy. Have Jack point it out in the first act as his father's, to characterize him.
Come to think of it, this goes double for red herrings. If they serve a purpose -- and a purpose equal to their development -- the reader won't be as frustrated when they don't pan out. When you don't, well, Aristotle skewer it a long time ago: