Perfectionism only enough for a draw

My latest game was at a rather more sedate time control than the high-octane 30/60+15 school match I had yesterday. Inter-county matches in the Southern Counties Chess Union (henceforth SCCU; that's Buckinghamshire, Essex, Hertfordshire, Kent, Middlesex, Surrey and Sussex) are played with 1 hour 45 minutes for 35 moves + 30 minutes to completion, so nearly the double the time. Perhaps I benefit from this, since my score in county matches is excellent; I have a score so far of +7 =4 -1. The game below was for Surrey's U-140 team, on board 12 of 16. We were away to Sussex.

As so often of late, the game was a Sicilian. My opponent played a little passively in the opening and early middlegame, and this enabled me to attain an early advantage with the black pieces. But I was unable to follow through. I was seeing the right moves, just not playing them! Every time I came across what computer analysis reveals to be an especially strong continuation, I dismissed it on account of some minor issue in the position that I disliked, failing to account for the bigger picture. Consequently, I was unable to land the killer blow, and my opponent took his chance to get into an early ending - I now had no advantage, and prudently offered a draw, in part for the team's sake. Though the game was only 24 moves long, we played slowly and thus were one of the last games to finish; we won 9.5-6.5 in the end but for some time the match hung in the balance and a loss could have been dire for Surrey.

It shall be necessary for me to shake off this unwelcome weakness in my play for me to improve - it has been the cause of defeats too when I have tried to avoid any and all weaknesses in a position and been overwhelmed rather than making necessary concessions. Also worth noting: with black, especially at higher levels of play, it is necessary to take risks to win, so this lack of compromise is especially ineffectual.