in 10:12-13 Moshe tells the people "What does Hashem want from you?just to fear Him, to go in His ways, to serve Him...to do the commandments... for your good"
Oh, that's it? Just to fear and serve Him? Oh, that's not such a big deal!!??All He wants from us is to keep the 613 commandments as written in the Torah and explained in the voluminous Talmud and codified in the voluminous shulchan aruch? That's it? Why didn't you say so??!! That's nothing!! So easy!! All we have to do is fear Him??!!
I think the key word is the concluding words of the verse "fro your good".
It is like a studious student in college. Sure he has plenty of work to do, homework, lessons, study, tests, labs, internships, etc. to get his good grades and succeed. But he does not think of it as so hard. He knows it is all for his benefit so he does it because he needs to do it for the success he is looking for in the future.
But we are more like the non-studious student. He looks at the work and does not realize that it is their for his benefit. He complains that it is too hard or the teacher gives too much work. Everything is a big deal.
It is a matter of approach and attitude. If we approach the Torah and mitzvos like the studious guy, with the knowledge that it is really for our own benefit, than it is easy. All He wants from us is x, y and z. But if we approach it looking just to get it done, than it is hard.