A quality of a good Startup engineer is "Finishing what you started". I value finishers more than people who talk good theory and start many things but don’t finish most of them. Most of the time people get excited and start many things concurrently but leave them in limbo or they finish 95% of the thing. Over 7 years at my current Startup I have observed that in many projects doing first 95% may take you X units of time but its the remaining 5% that demands 10x cognitive effort and time from you. Its this last 5% where people either burnout or give up. Its the finishers who keep the compass pointing to North star, never give up and do what ever it takes to Finish( in indian mythology saam, daam, dand, bhed).
Recently One of my respected colleague "Sachin" left for a sabbatical. He was one of the Finishers whom I would hire any day on my team or would choose as a buddy to watch your back. "Sachin" has a zeal like a Rhino or Triceratops to Finish what he started and for this I value him the most. Best of luck to him and I hope he gets bored with sabbatical and joins back :).