No matter what you may think, no matter what I may come up with in the gym, showing up and starting your first rep is by far the hardest thing.
I am speaking in general terms of course as I am very well aware that many believe it is the workout, specifically my workout, which is too hard. Imagine the irony that we who show up every day to do that so-called horrible workout think it is the warmup which is usually the hardest, that or just getting out of bed and showing up. When finally in the gym, starting that first rep, following the plan is strangely easier with each passing minute. Such paradise, of course, never lasts forever and sooner or later, things get genuinely hard but by that time you are enjoying the hard work being done and enthusiastic for being closer to done with each passing rep.
Figuring up why and how you get from your bed to starting your first rep is the hardest part of the process. Technically, it is the simplest thing, practically somehow it is still the hardest.
What I am saying is, do not lie to yourself how it is the workout which is hard, too hard or brutal. Showing up every day, doing your first rep of the day, is your ultimate lesson. If you can manage that, you can manage the hardest sessions I can throw at you.