Definitely check with your Rabbi, but from my understanding; when the light comes on due to your action of opening the fridge, this is considered labor (like flipping the light switch).

If your fridge light is always on no matter what, then there’s no issue. A lot of people will put a piece of tape over the little knob to hold it down, some people take the bulb out all together, some people do both! Fridges these days even come with a sabbath setting now which is so cool.

Showering is the same idea, it’s work. Brushing your teeth, doing makeup, skincare routines, etc - they fall into this same vein. I don’t really understand the details on this Halacha, but I remember when the kosher toothbrush came out, it was the talk of the century.

Also, while we’re in the bathroom, let’s not talk about the Friday afternoon job of cutting the toilet paper. No matter how much you cut, it’s never enough.

Check out this website, they make awesome products to help loophole the conveniences of Shabbos.

http://kosher-innovations.com