By far the most effective thing to motivate me to exercise, and run in particular, is the "VO2 Max" section of the Apple health app. It's a rough indication of your cardiovascular endurance, and the higher, the better. The real key is that, though, is that it basically works like an XP bar in a game: if you "grind" running, it goes up. If you don't, it doesn't. It's incredibly addicting to check the number every time you finish a run and see if it's ticked up slightly. It's also great because in some sense it is "real". If it goes up, I have an easier time on hikes, runs (obviously), playing sports, etc.
The second thing that really got me into running is that I found that the most effective way to get VO2 Max to go up is to run in heart rate zone 4, also tracked on the Apple watch. Zone 4 is 80 - 90% of your maximum heart rate. It's not an all out sprint, but you'll be moving pretty fast.
The reason it's so effective is best illustrated by contrast. In the past, I've tried tracking a number of metrics on my run: total miles, average speed, calories burned, whatever. But I found it psychologically draining to continuously try to top my fastest speed, and I inevitably had off days (or weeks or months) when the score I was measuring wouldn't go up. Obviously as you get faster, this happens more and more, and it gets easy to start wondering if you're even progressing. Heart rate is a much better measure, because in some sense this is compensated for. You don't have to continue to beat yourself every day (or fret that you're not) to get to 80% of your max heart rate, and on days when you're more exhausted, you'll hit a higher heart rate faster, so the effort is roughly the same.
Also, Zone 4 is a great place to be. You're pushing yourself, but it's a sustainable sort of push. I often found that when I ran sprints I wanted to die. They were so psychologically demotivating that I would do anything to avoid them. Zone 4 is not like this. It's very manageable, and I wake up excited to do it!
At this point, I want to run every day - I'm at the point where I have to force myself to stop sometimes because it's healthy to take rest days!
Usual disclaimers apply, BTW. Don't do all your running in Zone 4, don't immediately go from no running to an hour of zone 4 every day, do a reasonable ramp up over a long period of time, etc etc.