Customisation vs over fiddling.
I use a lot of software, and I am very picky about how the software I use works. If something does not work the way I want it to then it will start bugging me really quickly. This is pretty typical of the type of user I am, I belong to the elite group that are the only people that are both the most passionate and the most whiny about software features... the nerds.
In comparison to the real greybeards I'm a really new Vim user, but compared to new people I've used it forever. I first started using Vim in the mid nineties and I have had it on every machine since. I've only ever thrown out my config and started over once so far. I don't use it for everything, as I've explained previously, but I do use it a lot.
My Vim configuration is massive, probably to the point where there are parts I don't even really use anymore. It is hard to say if I've spent too much time on configuring Vim. I have gotten a lot of value out of the way I've set it up, but I've also spent hours on making it. Were those hours worth it? It's a bit hard to justify as I use it about as much as Sublime Text 2 these days.
For almost every piece of software I use I will open up the preferences panel after at most an hour of usage to see what I can tweak. I love changing little things if I think it will make the software better to me.
However, it is a fine line when it comes to software that you use to be productive. It is easy to fall down the rabbit hole of over-fiddling with settings rather than actually being productive. If you spend 12 hours tweaking colours in Visual Studio before you start working then that may be a bad tradeoff unless you get insanely more productive, but if you can spend 5 minutes on tweaking settings and that lets you be more effective then that is generally a net positive.
The problem is drawing the line of reason between good customisation and over-fiddling. I myself have a huge problem with this and I've started taking active steps to not do this.
So far I've found these things to help:
1. Export all the settings files you can when they are at a state that you like, and put them in dropbox, then you at least only have to do it once
2. Find out what you like, (fonts, colors, keybindings, etc) so that you know what you should be going for.
3. When possible, pick apps with sane defaults
Those things have brought my fiddling with the things I use to be productive down at least without making me feel constrained, so I would clearly recommend it to everyone else as well.