[Wingman4l7]

You've likely worn knit socks and T-shirts -- they're machine-knit. A lot of clothing is knit, not woven. Fabric does not have to use big and chunky threads to be knit; the loops can be quite a small gauge in size.

[MikeTheGreat]

Ah - that makes sense.

I was thinking of hand-knit clothing, which (as you say) tends to be big enough and chunky enough that you can see the stitches.

TIL - thanks :)

[eru]

You can take a magnifying glass to any old t-shirt you have around. Or these days, you can also just take a snapshot with your smartphone and zoom in.

Compare with what you see on jeans and dress shirts, polo shirts, dress pants, socks, etc. It's quite interesting.