Yes, can tie a reef knot. It is necessary if you want to wear a silk scarf, otherwise the ends stick up oddly.
I do realise that I sound like a Boden-wearing priss writing that, but I have more need of a reef knot for scarf wearing than securing tents.
Cannot mend a puncture, but the bike shop where I bought my bike does it free so haven't had to.
First aid and cooking a meal seems to be of more use than puncture repairs and knots.