... Oh come on, they don't taste that bad! Hell, "bad" isn't a word that I'd use for cucumbers in a sandwich. They taste fine.
Well, if the bread isn't buttered properly, you'll end up with soggy bread and mushy cucumbers, which is awful. Same goes if the cucumber is too wet (if the pulp part is accidentally included, or if the cucumber slices are not patted dry).
Of course, if you're eating the sandwich right after preparing it, half-assing it is just fine because there's not much time for the water to move from the cukes to the bread. It's only an issue if you're preparing cucumber sandwiches in advance for a tea party/luncheon or for lunchboxes.
(Actually, come to think of it, it's probably still a bad idea for lunchboxes, due to how delicate and perishable it is.)
Aah...
You're spilling...I see. I think you should be able to do it if you use a straw.Straw?That's right. If you use one of these, you won't spill.Hand over the bananaaaaa~!Sensei, I don't know how to drink neatly.*Gulp*Yes, that's very good.*Gulp**Spillll*BRPPHH!*Splash*Wah! What's wrong!?Jeez, don't fool around.I-I wasn't...
*Cough* *Cough**Streeeetch*The cucumber in sandwiches is the tastiest.*Uho!*Is Rum-chan going to be okay?Mother told me they're tasty in a sandwich.*Suuuck*Am I drinking neatly?LunchtimeFufufu! We've got you cornered!