The "WTF" list technique is great for this.

Every time you see, or encounter, something that makes you go "WTF?!??" you write it down.

Chances are you don't have NEARLY enough context yet to figure out why it's like that, and so barelling in to "fix" it is just going to lead to frustration and bruised ego's all around.

After a few months you'll either have crossed off things "Oh, THAT's WTF" or you have a list of things to start chipping away at, now that you have the FULL context.