Recipes that specify amounts like "juice of 2 lemons".
This is not a defined amount of juice. Lemons are variable in size, and people's abilities to juice said lemons also vary. Of course, this doesn't matter in every recipe. But in, say, lemon curd (or the lemon creams I just made), you want a consistent result, and if you use a different amount of lemon juice from what the recipe writer uses, you're not going to get that. Too little lemon juice, and it will either not set up or be sickeningly sweet.
Measure, people. Cups and spoons and scales were invented for a reason!
also, don't be a ponce and specify vanilla sugar. Not all of us store our vanilla pods in the sugar jar and we don't want to decide to make things 2 weeks in advance so we can. Include a vanilla extract substitution. It's not the stuff of the devil if you use the real thing. (And in my experience, it's simply not worth the effort to use pods in cakes and cookies. Save them for custards, etc where the vanilla is a primary flavor and there's steeping time to extract it.)
Am I being an anti-snob, or am I just a snob about snobbery? Don't answer that question. :-)
While we're at it, cooking with lemons is a surefire way to discover every miniscule cut on your fingers. Or not so miniscule ones, like the one on my left index finger from yesterday. Never slice a bagel when you're still half asleep. At least I cut my finger with a very sharp knife, so it was a clean cut! (Albeit quite a bloody one.)