Each generation back from yours has a higher chance of not having their genetic lineage ended by you not procreating. Most people will have siblings so won’t even be the end of their parents lineage, even less will be the end of their grandparents, I’d be surprised if there was anyone that could end the lineage of their great grand parents. Depending on your circumstances I’d say the only ancestors you have to worry about disappointing in a genetic propagation sense are your parents, and that’s only if you have no siblings.