My bass had no fret buzz straight out of the box

Then I had to tune the guitar, and even afterwards there was much buzz and rattle no matter how gently you struck the strings

Mine came with a little fret buzz on the A string, but a small adjustment of the truss rod fixed it right up (only 1/8th turn).

Unfortunately, from the very beginning, there was fret buzz

neck is straight no fret buzz ).

After the buzz became so bad that the guitar was unplayable, I put the heaviest string on it that I could find and tuned it up a half step (trying to bend the neck back)

Worst case scenario if you run into fret buzz