Leave early is definitely a no no.
If leave early that's called slacking off. Subject to HR for disciplinary action.

Leave on time you did nothing wrong.
Work overtime you also did nothing wrong. But don't expect company to pay you more.

If you can't get the work done. Don't care you work 8 hours or 8 hours 5 min. The work is not done..
This is why people don't want to work in environment where there is not enough resources.

You 1 person do 3 people's work also don't get the bonus.
Must learn from the seniors la.

They are hibernation mode... 5 days a week. Finish liao don't update.
But when boss ask for updates, immediately got update liao..

This office politics you must master in ST.
Must appear to be working. But don't work too much or you'll get arrowed all the time.

Just work enough. And see the environment... If people ot etc rushing. You also smart abit go home a little late. Or they will arrow you... "eh xxx so early every go home early,... Get him to help out"