ON a bad day at work Korean tour guide An Lomi simply counts to three to control her anger. But yesterday was a good day for Miss An whose simple, yet effective, strategy of handling difficult customers paid off. The mother of two was awarded the Hong Kong Tour Co-ordinator of the Year title by the Hong Kong Tourist Association. Miss An, who is originally from Korea but has spent the past 20 years in Hong Kong, speaks three languages - Korean, English and Cantonese. She said the biggest challenge she faced as a tour guide was a hotel room shortage which sometimes meant overbookings. Miss An, who handles groups of up to 15 several times a month, said Ocean Park was the most favoured destination for Koreans. ''I think I have lost my temper a few times, but I try to remember they are clients,'' she said. Miss An, who was selected from 10,000 nominations, won a trophy and a one-week study tour to London.