There are a lot of do's and don'ts when it comes to public transportation in Singapore.

Here are some familiar signs, for example:

New sign

But here's one sign that you may not have seen before:

The sign was first spotted by Reddit user u/theresjustme in an SMRT bus.

The sign was apparently pasted on both sides of the bus.

Keep legs to yourself

Apparently, the sign implies that commuters are not supposed to rest their legs on opposite seats, like this:

Tsk, tsk.

Not-so-common courtesy

Going by comments on the Reddit thread, some were surprised that a sign had to be printed for something that should be common courtesy. 

Give up seat to those in need

For now, there's no written rule about resting one's legs on the opposite on SMRT's website.

However, passengers are encouraged to offer their seat to those who need it more, especially the elderly, handicapped, pregnant women and children.

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Top image from u/theresjustme on Reddit