In your opinion was Victor being irresponsible for abandoning his creation to fend for himself or was it a smart decision in Frankenstein?
In Shelley's Frankenstein, Victor decides to abandon his creation and allow it to fend for itself. While there is surely opposing views on this, one could justify that he was ultimately wrong in his decision.
Perhaps if Victor would have taken responsibility for his creature, nurtured it, and taught it, the outcome of the story would have been very different (but then we would not have the classic many know and love today). All the creature wanted was to be loved and accepted by someone. The fact that his "father" abandoned him was heartbreaking enough, but, to add insult to injury, the creature was abandoned by society as well.
Therefore, if Victor would have taken responsibility for his creation and loved it, the creature would not have had the soul shattering experiences which caused him to seek out Victor and murder all whom he loved.