Are lemons sweet or sour ?

Interesting and funny after-work session this afternoon with focus on misleading your brain about what you are actual eating. After a short introduction we were divided into two groups, each group eating a specific tablet.
The group I was in got a red tablet, which we slowly should shallow. This gave us a taste impression of sourness, liquorice and onion. This tablet is blocking your taste buds towards acid/sour taste. The other just got normal sweet candy.

After we had shallowed the different tablets, we were each served a slice of lemon, which we should bid into. The other group having eaten a normal sweet candy found this lemon slice to acidic and sour, as anyone would expect. My group had the impression we were eating a slice of sweet of orange, so we kept eating our lemon slice to great disbelieve of the other group.

The other group now got the opportunity to shallow the acidic blocking tablet. After this we tried, how the taste of tomatoes was sweet and less freshing to eat, while strawberries (without sugar addition) became very, very sweet, and we simply could not stop eating these lovely tasting strawberries.

The effect of these tablets is around 2 hours, so the evening meal afterwards was interesting as well. The salad with sweet corn and cranberries left you with quiet a sweet impression, and the Pepsi Max was overly sweet and almost un-drinkable. Luckily you could also have plain water for the meal.