There is a book appeared recently called "Pragmatic Career" and there was a sentence in its annotation saying "when I started to look at my life throw the glasses of agility I started to see agile patterns just everywhere". Ok, that probably not the exact quote but the point is that some people getting the agility too far. They start to worship it almost as a religion and sure see its deeds just everywhere.
Don't get me wrong I'm not against agility and this is not another crapy article a la "agility sucks, I hate it". Nope, agile approach is a wonderful tool and I use it every day and pretty much happy with that. My point is that the agile approach is just a tool, you should use it wisely and be critical about it.
Agile approach works pretty well if you are an experienced developer, a ninja who knows how to give a good punch from almost any position. You don't plan too much, be flexible and if the things go a wrong way, you just adjust. It reduces the entry level, gives you ability to try this and that and see how is it going, etc., etc. You take all the advantages of the technique.
But when you are young, have a lack of experience and good habits, it might lead you to a wrong path. Because of it nature, people quite often start practicing the "shoot first think later" approach. They write crap and hope they will fix it later, don't write tests and documentation. They think that they are agile because they produce a lot of code and kinda buggy features which they gonna make better later. But in reality they go in circles over and over, and eventually spent an ugly amount of time.
Agile approach is not about creating crap now and make it better later, it's not about skip all the things you are too lazy to do or just don't know how to do. As the matter of fact, the original "Pragmatic Programmers" book in one of its tenants says directly opposite "Don't live with broken windows". More of that, any normal professional in any area will tell you the main rule of being effective "Do the things once and only once". If you need to get back and fix your solutions, you are just killing time.
Agility is all about flexibility and rapidness. It is a contradiction to the old fashioned heavy planning approach, a tool which lets avoid painful situations when you at the finish line and realize that you have not what you needed. With agile approach you do small steps, but it doesn't cancel the idea that you should do your steps right. You do small steps but each step should be done in a good way. If you rush to the end target, skipping steps and taking all the possible shortcuts, move by an unpredictable trajectory, at the end you will have something as much painful as if you was sticking to some wrong plan.
And the problem actually, the problem is in ourselves, it is in our brains, in the way it works. The mother nature designs the things the way they were working in the most effective way, consuming as less energy as possible, that's the matter of surviving, and our brains are not an exception. Instead of careful thinking, we tend to jump to conclusions based on our experience, on the things we believe. That's kind of solutions caching mechanism. And the agile approach fits it like a glove, you just make rapid decisions based on current situation and your guts and move forward.
The problem is that if you have right solutions in your cache/experience, you are good, but if you don't you'll go through all the problems and become one big pain in the butt, for yourself, for your colleagues and eventually for your customer.
And here we come to the sake of "evil" old planning.
Planning is getting evil almost the same way as anything else getting evil, including agile approach. When you overuse it. The sake of planning is that it lets you make the reality check, think critically, review your experience cache. You write some simple roadmap and ask yourself a question "How do I know what I know?". It lets you filter out problematic cases, make you aware about problems before you meet them. That's the way to make your brain actually work, not just return some first thing out of the cache.
The bottom line.
I think you've got the idea. Sometimes you should ask yourself what are you actually practicing when you are practicing an agile development? Don't you feel like going circles, getting back and fix the things all the time? How do you know about the decisions you made? Don't you call something useless just because you too lazy or just don't really know how to use it? If you have any hesitations, it's okay to stop, sit down and think about the things for 20 minutes, do some reality check, maybe even take a good old pencil and piece of paper and write down some short plan.
This will make you actually think about the things, which will make you better, and better you will produce a better work.