Name for problems with a short-term pay off but small long term cost? Is there a name for the types of human behavioural problems where making a particular choice isn't a problem, but making the same choice over and over again leads to a bad outcome? Where there is an immediate short-term pay-off for making the choice one way, but a small long-term cost to doing it?

Some examples of these types of problems are: 


weight gain  
personal debt
litter


I think it's a really interesting type of problem because you have to override the short term motivation many, many times to get the long term pay off.
I agree with @Fizz that there is probably no specific name for the type of problem in question, but the behaviour involved is referred to as self-control, or more loosely, willpower.  Thus, the type of problem can be referred to as a self-control dilemma:


  Self-control dilemmas occur when long-term goals and values clash with
  short-term temptations. ... One of the most common self-control
  dilemmas involves the desire for unhealthy or unneeded food
  consumption versus the desire to maintain long-term health. ... Weak
  temptations present more of a challenge to overcome than strong
  temptations, because they appear less likely to compromise long-term
  values.


and accordingly temptation:


  Temptation is a desire to engage in short-term urges for enjoyment,
  that threatens long-term goals.


Chronic failure to meet long-term goals / succumbing to temptations is called akrasia, or "weakness of will".  The opposite is delayed gratification - also see the Marshmallow experiment.