It's not easy to lift weights or do a circuit of bodyweight exercises. It's not easy to go for a run or do sprints. Should it ever get easier?
No, it shouldn't. Workouts should always be different and you should always push your limits to the max. What you did the day before should be easier the next time you do it, if you go at it with the same intensity, but to change- to see that improvement in your body's image and energy- you need to progress. Do more then yesterday.
You go to your gym, you walk in and it is time to work. You do your warm-up and get right into the workout. You know what you have to do. You are either following a coach, trainer, teacher, instructor- OR- you're following your plan, that you spent time writing out.
The day could be hard, slow, boring, frustrating or straight hell but when you get into workout mode you need to forget everything and do the workout. There's no excuses. Unless you fall over or limp away you do the work. It's not easy and it should never get easier. BUT- you want to improve, you want to feel stronger, you want to burn fat or build muscle.. So you kick ass every time and leave the excuses at home.