Even Peter thought some of Paul's writings were hard to understand .....even as our beloved brother Paul also according to the wisdom given unto him hath written unto you; As also in all his epistles, speaking in them of these things; in which are some things hard to be understood,
And that people were misusing paul's writings, as they did other writings too....
which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction. 2 Peter 3:15,16
So if you sometimes find things like Galatians, or other writings of Paul hard to get, you are not alone.
Ye therefore, beloved, seeing ye know these things before, beware lest ye also, being led away with the error of the wicked, fall from your own stedfastness. 2 Peter 3:17