I workout daily, and for my rest day, Sunday, I do Yoga.
I think it's all about understanding that you should take care of your body as your body does so much for you. I personally can't go to sleep if I skip a day; note that adopting the "gym rat" mentality also isn't all that healthy either, as you don't necessarily HAVE to go to the gym to get a good workout in, it's just a great place to do so is all.
Other than that, what you eat believe it or not motivates you to go to the gym, both directly and indirectly. Directly because eating well (and I'm not saying well based on what is advertised to be "healthy" but what actually is, such as Whole Foods and Non-GMO pesticide free foods amongst some), promotes proper balance of hormones and toxin removal from the body. You are what you eat after all, and your body performs better when you are well nourished. Indirectly because when you develop the habit of eating nutritionally dense food and discover that eating well doesn't necessarily burn a hole in your wallet if you're a smart shopper encourages you to make better decisions about your health. Not to mention of course that nutrition is one of the most important factors in seeing results in your workouts, apart from how you do the workouts themselves.
I live in Jersey and it snows frequently, with the Winter being cold, so trust me, I understand that sometimes you just don't want to leave your house when you finally get back home to workout, but if you push through and go, you'll see that after half a year or so of building the habit you'll want to go regardless of how bad the weather is.
Also, find what you love to do and cycle different major muscle groups (you can find countless articles online explaining why) on different days. If you really look forward to a specific exercise you'll want to do it. For example, I look forward to Tuesdays and Saturdays because I love Cardio.