They're OK, if you want to see fewer lows and highs make sure you sit down at the end of each week (or whenever is most convenient) and try and learn from your recorded data.
For example, on the 11th something went wrong at dinnertime as you were 18.1 before bed. Did you miscount the carbs in dinner? Forget your insulin? snack? Was it fatty food so took a long time to digest? Little insights like this are useful because hopefully next time you have that meal you'll be able to avoid the high before bed.
That's not to say you should beat yourself up after every low or high (if that were the case I'd be black and blue) but there's always something new to learn with diabetes!