Yes, the psychological effects of telling your opponent "I am going to ruin my pawn structure and give you a much better game by simply following opening principles and potentially go into a losing endgame" can be quite daunting.
While playing normally and blindly "following opening principles" may not get you very far in the Grob, with practice you can learn to tailor it into a powerful attacking weapon.
I think the Grob (1. g4) is a very underrated opening for white. Observe:
The aggressive stance of the Grob is sure to intimidate your unassuming opponents OTB. So why is it so rarely seen in tournament practice? I think it is because people underestimate the extreme psychological impact it will have on your opponents.
By employing the Grob, you bring your opponent into unknown territory from the first move and throw their hours of opening preparation out the window.
The moment you play the move 1. g4, you tell your opponent that you are an aggressive, risk-taking player. Add this to the fact that the Grob is an opening that your average tournament player will not be prepared against, and you have the perfect psychological weapon to employ at your next tournament or online game.
The Grob will be sure to shock your average opponent, and it will be easy for them to crack under the light square pressure you apply straight from the opening.
The Grob even transcends color; the opening can be played with the black (1…g5) or white (1. g4) pieces and the same basic principles can apply, minimizing your need to memorize reams of theory on mainstream responses to 1. e4 or 1. d4. The Grob is a true one-size-fits-all opening.
So why is it that people haven’t noticed the countless opportunities this opening can provide?
Players who doubt the integrity of the Grob may bring up some of the following points:
"The computer says the Grob is a bad opening in comparison to the more popular 1. e4 / 1. d4."
While Stockfish (Ver 1.0.5 at depth 29/42) may evaluate the position after 1. g4 as -0.57, this is still well within the drawing range and does not take the psychological benefits of playing the Grob into consideration.
“It doesn’t follow opening principles.”
Precisely why it is a more powerful weapon. By playing an unorthodox (but still powerful) first move that your opponent will not be prepared against, you immediately gain a psychological advantage.
This opening has stayed under the radar for too long, and I take it upon myself to enlighten players of all strengths about its many advantages.
EDIT: Agreed, in classical games the Grob may not be a good opening, but in blitz it seems to wield quite fair results.