Sometimes it happens that you simply cannot get along with someone, perhaps a friend, or a potential girlfriend (boyfriend). At first they appear to be the right person, but with time you notice that things are not as good as they seem.

There are many elements that have an impact on that: cultural differences, educational backgrounds, psychological traits, age, and so on. Some of these details (ex: age) are easy to 'obtain' and analyze, but other ones require more time (for instance, you cannot tell anything about someone's family values after talking to them for 15 minutes).

Things would have been perfect if we had all the time in the world to study other people, but reality is different. We have to move on, drop some connections, and establish new ones, because spending time inefficiently is a "passive risk" (passive, because you are not doing anything, and only later you realize that your inaction was bad; perhaps calling it a "latent risk" is a better idea?). We need a mechanism which allows us to tell how compatible we are with someone, even if we don't know them well enough to have sufficient data points for a reliable and accurate estimate.

This is where to-do lists come into action.

Follow up:

The first time the concept showed up when analyzing a potential relationship during a university class :-)

The idea was that when two people have different degrees of busyness, and different sets of responsibilities - they can't agree on which things are important, because they have different priorities. The busier person cannot dedicate time to "useless stuff", while the less busy person can afford that.

Naturally, everyone has their own definition for "useles stuff"; the busy person is bored, and feels how time is wasted, while the less busy one doesn't see a problem at all.

It's not an issue with the person, it's an issue with their to-do list. Alternatively, we can say that it is an issue with their inability to put themselves in your shoes (note that this works the other way around too!).

Some people are incompatible with each other throughout certain periods of their lives. You can't find time for them except only after 19:00, or only in the weekends; while they're free at 15:00 and have plenty of time to kill. When you meet, you're exhausted - they are full of life and eager to do something... contrast becomes evident after a couple of iterations. But don't blacklist them yet, perhaps within a short time they will get busier, thus you end up being at the "same level"?

Here is a checklist of items that will help you see things from the "to-do list perspective":

• Do they study in a university?
• Do they have a job?
• Are they involved in any activities other than studying? (if yes, in which field?)
• Which fields they are interested in?
• How much spare time do they have? (compare it with the your spare time)

By answering these questions, you can get a quick and "cheap" estimate of the "success rate". Like I said, it is not very accurate, but it is good enough when no other information is available. You don't need encyclopedias, you don't need psychological tests, and you don't need pencil and paper either. You can get your answers by engaging in a simple conversations, and your questions don't even have to be direct.

Notes:

• To-do list comparison should not be the only method you rely on when computing the "success rate". Do not "disconnect" someone unless you've taken other factors into account
• Comparing to-do lists is a great substitute for comparing ages; being only slightly more "expensive", this approach is inarguably better because it prevents you from "disconnecting" a potential friend simply because they are too yong
• When you think the problem is "I just hate her" or "he is stupid!", it is very likely that the real problem is caused by different to-do lists (and you just blame it on things that annoy you, things that otherwise would be ignored). This means that you should give them another chance, because when their to-do list will resemble yours, they'll become "friendship material". In other words, don't burn bridges.

* "cheap" and "expensive" means "easy to compute" and "difficult to compute";