To me I did the best I could implies you did your best inside the given circumstance and that was not the a single you've imagined or envisioned so you're thinking that it could be improved. Closing an email with Regards, or Form regards, is still quite common in britain, https://jaidenaq541.answerblogs.com/38205771/not-known-factual-statements-about-best-kpop-karaoke-gangnam-퍼펙트가라오케