There’s classic drinks like the black & tan or shandies; I’m talking more about the former. Mixing two or more beers together.
For example, someone gave me a six pack of a sour wheat beer (specifically, Creature Comforts Tritonia). It’s a bit much for me by itself, but mixed about half and half with a High Life it’s pretty good.
There’s a ton of Black and Tan type variations.
Going in another direction, however, I have a customer that loves Old Rasputin. Of every case I bring in, he probably buys 5 of the 6 four packs. One day I was talking to him about it and he mentioned that as much as he loves it, it’s just a little too much for him so he cuts it with some water. My beer salesman was in and over heard that. He suggested cutting it with light beer (miller lite/coors light etc). That way it still makes a little less rich/stout-y, but it’s, well, still beer.
(Re-reading the OP, I entirely missed the part about you doing exactly that).
Dogfish has a chain of microbreweries, one of which I used to live near. I haven’t been there in years, so I’m going by memory here. They had a “30” (which was more delicious) and a “90” (which had higher alcohol content). Aficionados would mix the two for what they called “60,” which retained many of the best qualities of each. My preference was to just drink the 30 first and the 90 later, same effect.
I’ve done that too. Or some other variety that I had a beer which was not just right in itself, but mixed with a different one made it taste better. Also I have used seltzer water on occasion to make a lighter beer out of a heavier one.
My Dad liked plain, ordinary Canadian lager beers from major commercial brewers. For some years, a well-meaning relative would gift him imports at Christmas, and on his birthday, and on other important days. Dad was happy if they were lagers like Heineken or Tuborg, but took a dim view of dark beers like Guinness. Which he got, a few times.
At such times, he would cut the beer into a half-and-half, or a black-and-tan, using Guinness and Molson Canadian. Since he used a half-bottle of Guinness and a half-bottle of Canadian, he’d pour a second, to use the other halves, and give it to me. (I was old enough to drink, so no worries there.) I found it to be awful–I could handle a Guinness by itself, and I could handle a Canadian by itself, but mixed together, they were awful. To me, anyway; Dad seemed to like them.
Ever after that, I told Dad to keep the leftover Guinness and Canadian for his second beer, and I’ll just have one or the other.