iPhone: If you're looking for a quantified self tracker, Reporter is an iPhone app that pings you with simple quizzes throughout the day and then collates that into graphs. The point is to provide an open platform where you can track all kinds of data.
Throughout the day, Reporter sends you notifications and asks you to fill out a survey. This means answering a set of simple questions. From the start, it has a handful of questions about how you slept, who you're with and where you're at, but you can add and customise the questions in any way you see fit.
After a few days of this, you can look back at charts that visualise your data. So, you can see who you've been spending time with, how much coffee you're drinking, or pretty much anything else you want to log and track. It's a simple way to log whatever you want, and the charts make the data easy to visualise. The fact that you can write your own questions, including how data is inputted (and outputted as a chart), means you can customise Reporter in any way you see fit.
The downside is that you can't compare two data sets, so you're not really able to see if there's a correlation between the data you're collecting. For example, it would be nice if I could see that on the days I drink 10 coffees I tend to also say I'm stressed out, or that when I play video game I eat poorly. Or maybe that I'm just a grumpy dude for the entire month of February. You can export your data into a spreadsheet, but you still have to put those charts together on your own. Still, as a place to collect and track any data you want, Reporter works great.
Reporter ($4.49) [iTunes App Store]