有什么事听起来容易做起来难？

What are some things that look easy but are difficult?
有什么事看起来容易其实很难？
 

获得171.5k好评的回答@Bibidh Subedi：

There are some very easy looking and easy sounding Guinness World Records. But, they are extremely tough when you try them out. I have listed some of them here:
有一些吉尼斯世界纪录看起来听起来很容易，但你自己尝试时会发现超级困难。下面列举其中几项：
Most Saltline Crackers Eaten in one minute
1分钟内吃掉最多撒盐饼干

The record is : 10
纪录：10块
Why it is difficult : The dryness in the mouth due to the salty crackers makes it impossible to go beyond 5 without water.
困难原因：撒盐饼干会使你口干，不喝水都超不过5块。
Most M&Ms eaten in one minute blindfolded using chopsticks
蒙上眼睛用筷子1分钟内吃掉最多的M&Ms巧克力

The record is : 20
纪录：20个
Why it is difficult : I could hardly eat 1 M&M blindfolded using chopsticks.
困难原因：蒙上眼睛我用筷子1个都吃不到。
Most CDs balanced on one finger
1根手指上平衡放最多的CD

The record is : 50
纪录：50张
Why it is difficult : Because, you aren’t allowed to poke your finger through the CD\'s hole. The CDs will just feel heavy and fall off when you try to balance more than 10 CDs.
困难原因：不允许手指戳进CD中间的孔，平衡放超过10张CD就会太重掉下来。
Most sticky notes on the face in one minute
1分钟内脸上贴最多的便利贴

The record is : 58
纪录：58张
Why it is difficult : Your face will run out of stick-able space after around 30 notes.
困难原因：贴30张左右脸上就没有可贴的地方了。
Most Marshmallows eaten in one minute
1分钟内吃掉最多的棉花糖

The record is : 25
纪录：25块
Why it is difficult: You need to have a standard-sized marsh mallow. After eating 10 marshmallows, it is difficult to proceed further without drinking water.
困难原因：棉花糖需要是标准尺寸的，吃过10块之后如果不喝水就很难继续了。
Most coins stacked into a tower in 30 seconds
30秒内把最多的硬币堆成一个塔

The record is : 69
纪录：69枚
Why it is difficult : The coin tower has to last for 10 seconds, but the tower will start losing balance after you cross 40 coins.
困难原因：硬币塔要挺10秒钟，但堆40枚以后硬币塔就不稳了。