I need a word for things not happening the way someone would want it to. For example, if you're at the ice cream parlor buying some icecream but they don't have vanilla, your favorite flavor, you would have to buy chocolate. Generic example aside, is there even a word for life not going your way? (One-two word answer, not a phrase)
You can probably call them mishaps:
- an unpredictable outcome that is unfortunate.
The Free Dictionary
If you are okay with being slightly crude, try:
This idiom follows from the fact that dogs very stereotypically urinate upon fire hydrants while out for a walk, supposedly as a way of marking territory. When you are the dog, you are the one doing the marking, you are in charge, on top of the world. When you are the hydrant, well, you are the one getting marked.
a haphazard life TFD
characterized by lack of order or planning; irregular; chance; random.
You imply that getting the chocolate ice cream isn't actually a disaster, despite its not being your first choice.
So maybe you'll accept your second choice. A pithier way of saying this is
which, according to dictionary.com, is
a strategy or plan to be implemented if the original one proves impracticable or unsuccessful.
The use of "Plan B"(R) as a brand of "morning-after" contraceptive rather underscores its suitability for the meaning you wanted.
Of course, there's always the possibility that you'll have to come up with a Plan C, D, etc......