Energy drinks are certainly one of those things you either like or you don't. Rockstar Xdurance has 200mg of caffeine per 500mg can, and both times I've had one since the caffeine level was increased I've certainly been extremely energised by them! It delivers a massive kick of caffeine quickly, and once it's had time to digest, by cripes it turns me into the Energizer Bunny
As for the mental triggers with comfort food, I do have to agree. Of course, to a certain extent, it will be a physical thing since the body still needs sugars and fats as part of a daily intake. That does quickly become a mental trigger though, junk food is good at triggering positive feelings in the brain after all.
When I'm having what I call a 'woe is me, I don't feel well' kind of day, be it from an injury, a super exhausting day or whatever, comfort food is certainly desirable. When I had two seperate weeks off from work a while ago, with injured legs, I was naturally not doing an awful lot of exercise. An absolute ton of sitting/lieing around watching TV/YouTube and a megaton of junk food to cheer myself up. I had no real physical need for such an intake, but the boredom factor kicked in, and I would feel better mentally for devouring an entire bag of popcorn while binge-watching Scrubs, or an entire pack of 5 jam doughnuts while watching a driver's eye view video on Youtube.
Thankfully though, the whole experience gave me time to actually take on a better view with food intake, a whole new outlook on having rest days from exercising and so much more. Not that that lesson stayed with me forever, I recently caused part of my injury to flare up again after going way overboard with quads strengthening exercises and hill climbing training on the bike...
This time, however, I am confident that I've spent enough time creating new neurological links. A few more days of rest and modified exercise routines and I'll be back out there riding again

Just I will actually listen to the need for a rest day this time! I've even modified my hill climbing training technique as I've typed this, so it goes to show what one can do with the right mindset.
Which leads me back to this thread's main topic. Getting fitter is all about the right mindset. If one wants to achieve a goal, getting into the right way of thinking has to be done first. We all have different ways of doing that though, and I can assure you my method would not work for the average person.
I've got to actually get ready for work, I've got a bit carried away with this reply!