Its a pity these "how much would you tip in situation X" threads can't be consigned to a more US-centric forum (I suppose at least that's where it started). The practice, and the nit-picking detail about individual tipping policies seems odd to those who rarely go to the US.

Last night I got into a taxi - traffic was terrible. The fare came to about US$4.50. I gave no tip - just the exact amount on the meter as I usually do. The driver returned the 0.50 to me, saying he was sorry for the heavy traffic.

Nice to be in Taiwan sometimes.