As a teenager, I came up with a set of four rules that I resolved ought to be guiding and unbreakable in going through life. They were, somewhat dizzyingly in hindsight, the product of a deeply sad personal event, an interest in Norse mythology and Captain America: Civil War. Many years later, I can't remember what Rules 3 and 4 were; the Rules were officially removed from my ethical code at age 21, and by that point I'd stop being so ragingly deontological anyway. I recall clearly the first two.

Rule 1 - Do not give in to suffering. Rule 2 - Ease the suffering of others where possible. 

The first Rule was readily applicable to daily life. As for the second, it seemed noble and mightily important, but rarely worth enacting. In middle-class, rural England with no family drama and generally contented friends, there wasn't much suffering around me. Moving out to University, one of my flatmates was close friends with the man who set up the EA group there, and on learning more about it I was struck by the opportunity for fulfilling my Rules that GiveWell and 80k represented. 

This story does not account for my day-to-day motivation to uphold a Giving What We Can pledge or fumble through longtermist career planning. I've been persuaded by the flavour of consequentialism used here, think that improving the experience of sentient life is wonderful and, quite frankly, don't have any other strong compulsions for career aims to offer competition. Generally buying-in to the values and aims of this community is my day-to-day motivation. Nevertheless, on taking a step back and thinking about my life and what I wish to do with it, I still feel about the abstract concept of suffering the way Bucky Barnes feels about Iron Man at the end of that film. The Rules don't matter to me anymore, but their origin grants my EA values the emotional authority to set out a mission statement for what I should be doing. 

I strongly recommend Small and Vulnerable linked in the post, but my motivation was much more mundane. I don't spend much money and my income will jump discontinuously after grad school so it doesn't hurt me to give.