1. Your coordination improves drastically
Before I worked in labs, I was a little clumsy - nothing dramatic, just the occasional lack of hand-eye coordination that happens when you don't need to be dextrous in your everyday life. Now? I have no problem at all opening flasks, bottles, and other containers with my left hand while aspirating a precise amount of cell suspension with a pipette gun in my right. I can pipette things into PCR tubes - and those tiny tubes for RT-PCR - with no problem; and after that, threading a needle is almost a piece of cake. Almost.
2. Presentation skills blossom into existence
After lab meetings, work-in-progress seminars, journal clubs, credited seminars, lab demos and other random presentations, I may still be nervous before I speak to a crowd, but you would never guess it. With the exception of that one seminar back in undergrad where my brain went #YOLO and made me completely forget all the nice segues I'd prepared for my slides.
3. Concision concision concision
There's just something about having only one page to describe your five-year project for grant applications that forces you to condense ideas until the resultant internal pressure and heat make them melt. Talk about a way to try (too hard) to make a joke AND to show off how much I've forgotten or misunderstood about physical chemistry! In any case, this post is definitely not an example of this, but writing a complex subject up without the luxury of playing with font sizes, margins or line spacings is a challenge, and you eventually have to learn how to cut to the chase.
4. You learn a new language (almost)
Have you ever read a scientific paper? It's not standard English, it's an entirely different written dialect. The first few times I read papers it took me a ludicrously long time to understand what was being communicated, not only because I'd be reading about material that was new to me, but also because of the particular idiosyncrasies of the language as used in that particular context. Here's a fun experiment you can do: talk to a scientist about the latest project for which they've written up a grant, and you'll witness them code-switch between conversational English and scientific English when they start quoting what they've written.
5. You become a better procrastinator
I should be working on something else right now, but I decided to take 25 minutes and type and barely edit this (shitty) post instead. Hey, I am totally currently working on my composition skills right now! And getting into the habit of sitting down and typing at a computer while thinking about my past experiences will totally be useful later on, when I write my thesis, right? Plus, there's nothing like procrastinating on exams or assignments by going to the lab, starting an experiment and pretending that that productivity compensates for your lack of productivity in other areas on your life.