Honestly, it would be a pretty lame T-shirt.

One time a colleague and I found that book just chilling under an unused desk at work. We had never heard of it, so we were pretty confused. 😆 Still kinda am, honestly.

I think the phrase has the same basic problem as a lot of common advice... the real truth is more nuanced than any pithy phrase could ever be. At best, it's a quick way of reminding someone who already knows better but has temporarily forgotten.