Or about how "flexible" you are.
Or about six pack abs.
Or about the person next to you doing a headstand while flossing their perfectly straight, perfectly white teeth.
It is not about being "good" at yoga, or being "fit," or being attractive/skinny/bendy enough to be allowed in a yoga studio, though it seems most yoga magazines and yoga stores if not explicitly, than implicitly through their use of photos and ads, create these rules.
We have enough places/magazines/brands telling us to feel bad about ourselves
Yoga doesn't have to be one of them.
In fact, my favourite explanation of what yoga is comes from T.K.S. Desikchar, in The Heart of Yoga. Yoga, he writes, can be defined as "attaining what was previously unattainable." He goes on to say, the starting point for this thought is that there is something that we are today unable to do; when we find the means for bringing that desire into action, that step is yoga."
That step could be finding a way into a pose that's comfortable and steady for us or learning to examine our own reactions to a given situation. But, Desikachar writes, "the practice of yoga only requires us to act and to be attentive to our actions. Each of us is required to pay careful attention to the direction we are taking so that we know where we are going and how we are going to get there; this careful observation will enable us to discover something new."
In this explanation, there's no room for should be. There is only room for what-is, for coming to the self and the world with alertness, curiousity and attentiveness. And it's those little acts of attentiveness that add up to a life.
And for that, pants are optional.