WordPress is messing with my posts code!?

I can’t figure out why it’s doing this. Through the code editor i’m entering:

<p>Beginning of post</p>
<blockquote><p>This is the quote</p></blockquote>
<p>End of post</p>

And it changes it to this (in the code editor once I save it):

<p>Beginning of post
<blockquote>This is the quote</p></blockquote>
<p>End of post</p>

And then when I view source it in the final post it shows it as:

<p>Beginning of post<br />
<blockquote>This is the quote</p></blockquote>
<p>End of post</p>

AHH! Why can’t it stop messing with my code?