The main thing I've always heard is that you're supposed to avoid "negative" angles on your wrist when typing. So I have a very thin, flat keyboard that I normally use.

Laptops are a similar concept, but they are raised up enough that my normal typing posture doesn't work that well. With my Inspiron that I have at home, the base of the laptop is thin enough and angled decently that it works out fairly well.

The Thinkpad has a base that is almost an inch thick, and my hand is just the perfect size that the hard edge I referenced is exactly where my wrist bends, which is I think what makes things so uncomfortable when using it.

It's not just negative angles but any deviation at all, really. Your wrists are not supposed to be sitting at a static angle all day long, and having physical pressure from the desk/laptop on the underlying nerves and ligaments is a know factor favoring RSI symptoms.

TIL I've been doing it wrong for thirty years.

Only being slightly facetious. What's going to happen to me if I don't mend my ways?

Honestly? RSI is always a risk. People don't have the same propensity to experiencing it though. I'm late 20s and it already started destroying my wrists, fixing my positioning relieved (most of) the pain.

I just can't type like that. I'm a very lazy typist.

I used to say that too until I started experiencing RSI. I eliminated 95% of the pain just by fixing my typing ergonomics. YMMV ¯\_(ツ)_/¯