The fallacy of _____ is committed when a disjunctive ("either... or...") premise presents two unlikely alternatives as if the were the only ones available, and the arguer then eliminates the undesirable alternative, leaving the desirable ones as the conclusion.

e.g. "Either you let me attend the Pink concert or I'll be miserable for the rest of my life. I know you don't want me to be miserable for the rest of my life, so it follows that you'll let me attend the concert."