Sometimes it's necessary, and even healthy, to take short breaks. After all, if your body's telling you it needs rest, you shouldn't push too hard or go into burnout mode. Going a long period of time without working out, however, starts to have an effect. If you go longer than just a couple days without some sort of activity or work out, your body will start to shift. It won't be sudden and you may not even notice it. But slow, subtle changes will begin to present themselves. That's why it's important that you find ways to remain active when veering from your workout routine.
In order to gain some knowledge (and potentially motivation) for the next time you want to skip your workout for a few days, read through some of the things that start to happen to your body.