The specific situation that inspired this question was that a functionary was typing my information into a system on a mobile phone and was struggling to get it right. While I can think of lots of preventative solutions, in the moment I simply asked him if he would like me to type my information (as it is different than most of the information he encounters). He refused this help, and after a few more failed attempts I again gently offered and he again refused. The whole time, a few dozen people were in line behind me, getting restless and upset that this process which normally takes 30 to 60 seconds was lasting for several minutes. I can't very well force my assistance upon him, but his refusal of my assistance caused suffering (albeit fairly small suffering in the grand scale) for other people.
While this specific situation caused me to start thinking, the general concept can be applied to many situation in which you see suffering occurring and you have the ability to quite easily relieve that suffering if only another person will allow you to take action. What ought one to do in this type of situation? Should one just stand by and allow people to suffer, while occasionally gently nudging/offering a better option?