You'll also gain the respect of the more muscled members of the gym with your dedication. Google the Stronglifts 5x5 weightlifting program. It's perfect for beginners, or those who have been away from the gym and want to see results.
As to your original concern about motivation, I find getting started is the easiest motivator. I may feel like uninspired walking into the gym, but after a 10 minute warm-up, I'm feeling better.
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If you can, help others; if you cannot do that, at least do not harm them.
~ Dalai Lama