Based purely on longevity, Star Trek gets around to a story about everything eventually, and in "Realm of Fear" we get a 24th-century analogue for the fear of air travel. Our resident neurotic, Lt. Reginald Barclay, is in mortal terror of going through the transporter, particularly in this case where the interference is bad and the transport cycle will take longer than usual. But despite the fact that going through the transporter disassembles you "molecule by molecule" and puts you back together again, Geordi nevertheless reassures Barclay that the numbers over the decades (and centuries) are irrefutable: "It really is the safest way to travel."
If you're going to do a transporter-phobia episode, I guess it makes sense to use Reg Barclay. Dwight Schultz is suitably game, perhaps even excessively so, taking his ever-twitchy persona into the realm of fear, panic, and hypochondria. One mildly amusing scene shows him convincing himself he has "transporter psychosis" when he listens to the computer list all of its symptoms while he realizes to his horror that maybe he's experiencing all of them. And how I love that Troi is able to prescribe for his anxiety the treatment of "plexing" — tapping with his finger behind his ear on a bundle of nerves. Whoa — I guess 24th-century medicine has totally evolved beyond the need for pharmaceuticals! (But of course it hasn't evolved past the point where Troi can relieve Barclay of duty simply for being somewhat on-edge. Sigh.)
If you care about the plot of "Realm of Fear," you are likely to be sorely disappointed, as this is a pretty low-octane affair. It features little in the way of compelling procedural TNG problem-solving and instead a lot of meaningless technobabble for technobabble's sake. The mystery surrounding the missing crew of the crippled science vessel is developed with so little urgency that it plays as background noise. The real point here is Barclay's transporter fear.
Naturally, the key to the mystery ties into Barclay's strange experiences while in the transporter beam, thus forcing him to confront his fear while simultaneously solving the mystery of the missing crew members. Unfortunately, the pedestrian plot is not compensated for by a compelling character story or any real psychological drama. It's all just kind of there in front of us, forcing us to shrug. Watchable, sure. But it doesn't leave so much of a minute's lasting impression.