Often many of us stick to the same schedule of going to the gym and working out with barbells, boxes, and kettle bells, constantly training to harden our bodies becoming faster stronger, and more fit, however with that consistency and familiarity we become comfortable to a certain degree. With that sense of being comfortable, we also often lose the mental challenge of overcoming unpredictable, uncontrollable variables that ultimately make us tougher. How many people do we know that have a certain barbell they use, or certain pull-up bar, have to have certain music, or even have a certain spot they like to be in? These "necessities", make us feel more mentally comfortable, but also keep us from gaining mental toughness. Is using a certain bar or certain spot really necessary to your success? In my opinion, the only thing that matters in a workout is your heart, your drive, and your mental toughness. Although many people may disagree with me, you can train mental toughness. Mental toughness can be trained by putting yourself into uncomfortable situations, for instance go running in the wind, exercise outside in the snow, train in unpredictable, uncontrollable, uncomfortable circumstances. This could even simply mean that you make a focused effort to push a little harder in a workout, shut off the music, use a different bar, ditch the chalk bucket, wrist wraps, weight belts, and knee sleeves, and challenge yourself to get out of your comfort zone.
Disclaimer: Safety always comes first, don't compromise safety for toughness.