Here's how I look at it: I want to be like those borgs on Star Trek who get hammered by photon torpedoes once or twice and then after that they don't take any damage at all. I want Commander Worf to turn to the flight deck crew on the Enterprise and say in that low pitch voice of his "Boris has adapted!".
I want my body to adapt to training because this means progress. I hate acronyms as much as anyone, but SAID (specific adaptation to imposed demands) is a pretty useful one to remember and regurgitate when you want to sound like a fitness professional or if you need a mantra to keep you in the squat racks. Constant soreness and extreme fatigue are fine if you like pain, but that doesn't mean you're making a beeline toward improved performance in your strength related endeavor. Specificity is king and the king maintains rule with consistency.