Mess with the bull, get the horns.
And then...
Take the bull by the horn.
Too many bulls, isn't it? It sounds like bullfighting. Just imagine, an angry toro ready to trample whoever is in front of him and the matador dressed in shining traje de luces, is waving away the red cape. The bull gets angry and it charges towards the matador; the fighter dodges. The bull turns around; his bloodshot eyes show how determined he is to kill his opponent. The bull-fighter is confident and calculating what that stubborn and angry bull is going to do. She accosted the bull waving the red cape furiously. The bull charged at her faster than before but at the opportune moment, the matador jumped out of the way. Our toro is wearing down and our brave fighter can see it clearly. When the bull charges again, she shifts; bringing out her sword, she kills him in one swift motion. What? You haven't heard of a lady bullfighter before? Geez.
I know the first two statements were just idioms and I completely went off the track and painted a different scenario. But, am I really that off the trail?
The first saying isn't too difficult to fathom. If you provoke someone, necessarily or unnecessarily, chances are you'll be facing hostility. Well, don't antagonize someone unless they are screaming for it. Now now, do you have to take every single one of my words seriously? Don't.
The second one (oh I like that one) depicts that if you want to be friends with a bull, you first grab its horns and start tickling. That is what being completely off-topic looks like. Back to the topic at hand, I'm sure you all know the things you gotta put yourself through to accomplish a seemingly formidable task at hand; you have to charge ahead with bravery and confidence.
So, yes, the two idioms have no relativity in between but aren't you curious about the usage of "the bull" in both cases. On one hand, it shows that we'll face consequences of our belligerent actions whereas the other shows that in face of adversity the needful is done. The bull in both scenarios seems indestructible and may even be inescapable.
Idioms, proverbs, and fables are a way to makes us understand situations better even though they are riddled with metaphors. They have a far deeper meaning than they project on the surface. You remember reading Aesop's tale when you were younger; I bet it would freak you out if a monkey or an alligator or a fox comes up to you and talk but those tales gave us the understanding of to-dos and not-to-dos. We learn something from everything, from stories to over-the-top metaphors to actions taken by others; there seems to be no shortage of things we can learn from. Even from the things where nothing can be learned, is a message that we get that there's nothing to grasp from that situation or subject.
So, a bull may not directly teach us something but its behavior may allow us to determine how the circumstances would unfold. They might not be useless after all, eh?
What it appears to be isn't what it actually is.
What it doesn't look like to be is probably what it actually is.
The bull is a bull and many metaphors as well. You can be brave enough to face the problem head-on and not mess around too much to blow it up on your face. Just keep your eyes open and perhaps you'll do just fine. Isn't that right?