This is the other problem when passengers complain. They naturally have a very self-centred view of their journey....they go for their train from their station and if their train is late or cancelled they are not happy. This is absolutely and totally understandable, but what you have to remember is that your fifteen minute journey is a tiny proportion of the total miles that the particular train you're getting on is going to travel during the course of the day......They are as a proportion of a 15 minute journey though...
Any delays that train incurs on any one of the journeys it makes will have a knock-on effect for the rest of the day....and as well as worrying about where the train is throughout the day, train planners also have to worry about where the driver is, because, like any sort of driver, they can only work so long before they have to have a break, and they also have to travel to work...usually on other trains....which may have been delayed....etc etc etc.
Hey, guys, I am a rail passenger too as well as a rail worker. I've stood on a cold platform waiting longer than I should have done for a train, and I've got frustrated about it!
The only difference between me and you is that I have some insight into why things happen.
(and I don't mind being a "punchbag" - as above I do understand passenger frustration! My mission is to educate! If even one person stops to think a little more when they hear that announcement saying "I'm sorry to advise...." and is a little less vitriolic when they speak to a member of railway staff, then my work is done )