​Often times I see two extremes in the gym:  people don’t want to push themselves enough, or people want to push themselves too hard.
When it comes to being most productive, the ideal state is somewhere in between.
What’s the worst-case scenario if we don’t push ourselves enough? 
Sub-optimal results, i.e. Wasted time.  Few things are more frustrating than putting in time and effort that don’t yield the results we were hoping for.
What’s the worst-case scenario if we push too hard? 
Burn out and injury i.e. sub-optimal results.  Again, putting in massive effort only to not see long-term progress (because you can’t be consistent if you’re injured) is not what we signed up for.
So what should the ideal state feel like? 
If you think in terms of school or work, you can make easy comparisons. 
There are times when you need to push hard- an accountant around tax season, a student during finals, a sales rep in their final week to meet quota.
There are times to take it easy; times in fact when we don’t have the mental energy to push through anymore.  This usually comes directly after one of the above examples.
But most of the time, a work day starts with a plan, and we go about executing the plan without massive pressure.  It’s not easy, it is work after all, but (hopefully) each day is not do or die at the office.
And as we all know, the more consistent we are at working our plan on our average days, the less we have to stress around those deadlines.  The student who does his reading and homework each week has far fewer all nighters during finals week.  The sales rep who prospects each week usually hits their quota before the quarter is over. 
So, in terms of working out and what should it feel like, just remember:
If it were easy, everyone would be doing it.  If it required a redline effort every session, no one would be doing it.