Capturing what you see, especially in an urban setting, is never easy. With an SLR or DSLR, a person, or people may get in your way, your subject may move or the moment may slip away; it happens.
Shooting on the fly using your phone at times, may come with its own set of issues. You may get a phone call while framing your shot, your phone may freeze or you may not have it out fast enough to capture what your eye had just seen.
This photo is 100% not what I envisioned; I was riding the escalator up when I saw a group of people walking down, they were backlit perfectly and when I went to grab my phone, they had passed. Although the moment was gone, I chose to still shoot and see what I could work with. While it's not what I had in mind, it's not horrible. Whether it be film, digital or mobile photography, at times you just have to play the hand you're dealt.