Sometimes during runs... okay, many times during runs... I rely on outside sources for motivation. Music, mostly. I construct my playlists with great care and probably overthink things sometimes. I get a bit too technical sometimes and try to plan out what song would best serve as motivation for me in, say the 35th minute of a 10K when I know that I'll probably need something heavy there to keep my legs churning, or in the 50th minute of a 10K, when I know I'll need something really heavy to get me to the finish line.
A lot of the times, the music serves as a prod to poke me and get me going a bit stronger during runs. But I have to have the right mentality and mindset before going out on the run, because if I'm not motivated or go half-assed into a run, no song is going to motivate me.
You've got to get yourself motivated before a run, before a walk, before a workout. There is a process to it, really. You've got to want to do something (run 5 miles, for instance), motivate yourself to doing it (grrr) and then go out and do it (huffing and puffing). Afterward you can celebrate (yay).
Perhaps that's a bit too simplistic but that's my process, in a bare-bones kind of way. The easy part is wanting. I want to go on lots of runs, all the time. The rest costs work and effort. Now, music mostly only serves as in-run motivation, but I do get motivated sometimes by other entertaining means.
Movies can serve as good fodder for motivation. There are countless scenes that inspire, that hit some deep-down nerve and make lasting impressions.
I can make an endless list of movies that were inspiring in some form or another, that provided some sort of fodder that I've hung on to or chewed on or pondered or whatever.
But there are some movies that have stood out more than others. Scent of a Woman would probably make my Top 10 favorite movies of all time. That's a daunting list to comprise and I don't know that I could ever make a definitive Top 10 list. But it would be hard to keep Scent of a Woman off that list. The performances alone are memorable, but outside circumstances also make it worthwhile. I first watched the movie when I lived in Mexico as a teenager. Plus, I had made it a tradition to watch the movie every Thanksgiving, something that lasted from about '94 until 2000, so for six years (Mrs. LB wasn't keen on the tradition, though now she might be more open to it). I do plan on resurrecting it. If you're not up on the movie, it takes place during a Thanksgiving weekend.
And if you're not up on the movie or haven't seen it before, perhaps you might not want to watch this, since this is one of the last scenes of the movie.
But this always gets me going, and if I could bottle up the feelings I get while watching this I'd be motivated for 10-mile runs every day.