Todays society is built around moderation, to a fault. You can't drink "too much" coffee or people think it's bad for you. If you eat "too much" red meat then everyone thinks you're going to die. If you spend "too much" time exercising then you must have a problem or be some narcissistic bastard.
While moderation is important for a lot of things, sometimes it's appropriate and even preferred to go balls to the proverbial wall. There will be times in your gym life when you just need a change, and approaching it with a well-planned moderate approach will leave you with nothing besides what you already had.
The aspect that made me think of this post in the first place has to do mainly with mobility and soft-tissue quality. As a personal trainer, I commonly saw adults show up for their sessions with 20+ years of poor posture and awful mobility built up. They'd been sitting at their desks at work for years and years and things had built up to pretty epic proportions. The punishment needs to fit the crime, and having these people roll around on a soft white foam roller for 5 minutes and then do some dynamics just wouldn't even create a dent in their bodies.
These people have such significant blockages built up that they need some seriously aggressive and dedicated work to fix these issues. Break out the bands and lacrosse balls or, even better, send them to a knowledgable manual therapist who can help break up their soft-tissue restrictions and restore their movement quality.
The same holds true for almost anything in the gym. If you've been lifting for 5 years and have hit a squat plateau, it's probably time to take some drastic measures for a phase of programming to get that thing trending upwards again. Too, if you've been eating a clean moderate diet with some cheat meals sprinkled in but you just can't get those abs to pop the way you want, you probably need to buckle down and make some serious changes to the way you eat for a month.
Keep in mind that this "whole hog" approach is something that should only be done sporadically throughout the year. If you approach something, like strength training, 100% balls-out for too long a period you're going to end up hurt and exhausted without the results you really wanted. Don't be scared to ditch the moderation, but understand when it's still applicable.
Have a great day and go lift some heavy shit!