Hongkongers are being encouraged to give visitors a smile as a small but significant step towards improving service quality in the city’s tourist sector, where unfriendly welcomes in taxis, shops and restaurants are not uncommon, the Tourism Board’s new chairman says.Pang Yiu-kai, who took over at the helm of the city’s tourism promoter last month, said on Tuesday that unfriendly taxi drivers, wait staff and retailers, as well as poor Wi-fi and telecoms services, were the top complaints by…