Libra natives love to socialize, and always have packed social schedules. On most nights, you're double or triple booked, trying to see everyone, and do everything.
For you to refuse a social engagement would just go against your sense of tact. Your sign respects other people a great deal.
You'd never hurt a fly if you could help it. So you want to make sure each person you meet feels special and appreciated.
Anything else would be positively impolite, as far as you're concerned. Using your innate tactfulness ensures that your relationships continue for a long time into the future!