Lemons for me is very often people cutting me off in traffic. Usually that happens (or catches me unawares) when I aren't paying attention. So when I get those kinds of lemons it reminds me to start paying more attention to where I'm going. Look around, be present, see what people are going to do before they do it. Usually, once I start paying attention, even when people cut me off I see it early enough that I can just steer around them, or I find that it just doesn't bother me.
Since I'm not the type to just happily "make lemonade" (because I don't believe it just passively accepting some of the crap that life (especially if by "life" one means "other people") throws our way). I'm more the type to throw them back and keep throwing them back until whoever thinks they can hand them to/throw them at me figures out otherwise.