One of the professors in my department (Public Health) works out in the Student Rec Center like I do. It should just be called the Rec Center because it is there for all of us. Anyways, his research and work regards work site wellness programs. Individual level factors that can improve health or increase risk of disease are his focus.
I have run into him in the gym the last couple of Mondays. Today as he was coming back into the academic building, he said, "I thought these workouts were supposed to get easier." To which I replied, "No, they aren't. If they get easy it means you're doing it wrong." He laughed and said, "That's exactly right." Because it was - but I knew what he really meant and he knew what I meant(gym rats think alike).
I did follow up my comment by mentioning some friends or relatives that I have who don't understand (or choose to ignore)that the weight training piece of their workout needs to be periodically revised.
But put that aside a minute. I want to break this 'easier' concept into two parts.
There is a physical and a psychological component to weight training. I make this distinction because I don't want anyone who is considering starting to exercise or who is new to exercise to abandon all hope and run back to the couch.
Psychologically it DOES get easier. It becomes a routine with benefits. Emotional well being, strength, conditioning and better metabolism are a few of the pay offs.
As people who are new to exercise and many older exercisers are uncomfortable with the progressive nature of weight training - i.e. adding reps, weights and new routines, I offer this link to a CDC page which offers suggestions on how to keep those workouts working for you.