Sure, you can get momentarily amped up by watching inspirational videos, reading motivational quotes, or reminding yourself of your goal, but all that's just a Band-Aid. What works for real is loving your training. That way, you never have to get motivated or psych yourself up – you can't wait to go train.
I've come to a conclusion from analyzing my progress over the years: if you train hard and eat well, you'll end up with the same body regardless of how you trained (keep in mind that I'm talk about lifting). Oh there might be some slight differences, but not as much as you think. Of course, I'm talking about natural lifters here.
But honestly, if you train hard for 10-20 years, the end result will be the same from pretty much any type of training: you'll reach your peak muscular development. Some muscles might be a bit bigger, others a bit smaller, but not enough to make a huge difference. So, just find the type of training that fits your neurological/psychological profile.
Find What You Love Doing
I love low reps, heavy weight, and explosive stuff. So I decided to keep doing that. In the past I "forced" myself to do bodybuilding work because I convinced myself that I needed it to get the body I wanted. Turns out, in the grand scheme of things it didn't change anything. And for me, high-rep pump work, drop sets and the like, killed my motivation because it didn't fit my neurological profile.
I also never did well on programmed plans – routines where the loads were calculated three months (or more) in advance and where each workout was planned months ahead. These completely kill my motivation. I can't stick with them for more than two weeks. I was always my strongest when I changed my training every week or two. But that's me. Others can be the opposite.
Stop worrying so much about doing a program because "it's respected" or because it's written by a coach you respect, or had rave reviews on the interwebz. Train the way you enjoy because you'll train harder and be more motivated. Just make sure your training isn't completely unbalanced (only chest and arms).