Let me first preface this with a couple facts about me. I am not a physicist, nor have I ever taken any classes in my life to warrant any extensive knowledge on the subject. I'm a software engineer by trade but have a great interest in physics (or at the very least, spacetime and how it all "works"), so I apologize if my question is elementary. For the past few years, I've been mesmerized by time dilation. I've read a lot about it and I understand what it is, but the "why" it is doesn't seem to add up for me. When I read about time dilation being a result of gravity and speed, I don't understand why those two factors have any influence on the object's time, whether it is in motion or standing still in space. To me, it seems the only factor here is the speed of light, and without an observer, it's all irrelevant. Let's say I'm moving at 0.7c toward a planet (let's call it B) in another system, and my starting point is Earth (A). Now, I don't know the math here, but I do know that my actual passage of time would not be slower. My perceived time of B would be much faster because I'm receiving the light from it at a much faster pace than the inhabitants are on that world, and if they saw me coming, it would appear I am moving faster than my actual speed. Of course, the reverse of that would be the effects on A, which would appear to be moving much slower, since I'm receiving its light information at a slower speed. Conversely, if I made it to B, only to make a return trip to A, shouldn't my total "trip" time passed equal that of the time passed on A? If the answer to this question is "yes", which I'm hoping it won't be (and can be explained for my further understanding of this), then why are speed and gravity considered in time dilation at all?