"So doc, I have to ask..." Marty McFly remarked as he and Doc Brown were in Doc's lab at night on a rainy Saturday, with Marty looking for some things Doc Brown needed to fine tune the DeLorean time machine. "Is the 2015 we've been to... is it still there?"

"Well... not exactly." Doc Brown explained as he brushed back his white hair. "You see, what ever little things we do in the present, or the past, could easily change the future. Hell, the very fine tune up we're giving to the DeLorean is already having an affect on the future as we speak!"

"...I am gonna end up rich, right?" Marty replied with a sensible chuckle as he leaned in towards Doc Brown.

Doc Brown shook his head. "Marty, what have I told you? No one should know too much about their future. Besides..." He patted Marty on the shoulder. "Our futures aren't written yet. It's what we do with the time we have now that counts, so make it good!"

"I hear ya, doc." Marty replied, proceeding to grab a nearby wrench as he accidentally slipped, landing on his back.

Doc Brown gasped as Marty laughed it off, with Doc Brown eventually joining him in chuckling.