Strength in the next Generation...what is the answer?

So here is an additional musing after our conversations tonight. How did the next generation please God to be able to go into the Promised Land? Why didn't they get their own 40 years of waiting? And here is my thinking on it--relating to my conversation concerning the difficulty of perservering and having faith when your mentor, your "human guide" starts to faulter and doubt and become bitter. These kids that made it to the promised land were just that, kids at the time their parents, mentors, grandparents, etc doubted God...said they would rather have Egypt than His way and basically snubbed their nose at where God was leading them and at what His promises were...I would say they were full of bitterness and doubt.
So does anyone know...how did these kids end up differently? How did they overcome the previous generation's laments and bitterness....how did they take a different approach and follow God or please Him so that they were able enter the Promised Land? I mean it isn't like they were in a bubble for 40 years and the months prior and didn't hear the lamenting of their elders and their elders doubt, and sit around the campfire and be inundated with that line of thought. So my question is...what was different...I think the answer to this would help at least me. ( I myself will be reading further in Numbers tonight to try to find the answer...)

I want to be the person that through the battle can see the joy and not just the doubt and the emptyness...that can sing when the lions are approaching...and can worship when my flesh is burning. That is my prayer...that is my goal...to be so clairvoyant on Christ and His purpose and His goal that all else falls away and I become one with my Savior and my God--and therefore find peace ONLY in Him and everything else (material possessions, etc) is just a bonus.
As a wise gal said tonight (paraphrasing) it sucks to be human... :) and yet I must add that it is good because we get grace along the way.