It could be related to your insulin management.
For example, the other person may have more "spare basal". If we are on MDI we take one or two basal shots a day and assume our needs are the same for 24 hours. However, we may need more basal during the night when we are lying around doing nothin but sleep compared to when we are running around during the. So we take enough basal to stay level over night which means we have "spare basal during the day. The daytime/nighttime basal ratio may be more pronounced in some people than others.
Another thing may be the time of our bolus. Different food taking different lengths of time to be digested and start to affect our blood sugars and this speed of digestion will be different for different people The speed fast acting insulin works should be the same most of the time (although it may differ for different people). In an ideal world we match the time the insulin starts working with the time the food takes to digest. This is very difficult but, typically, pre-bolusing (injecting about 15 minutes before eating ... although this time can vary from person to person and food to food) helps avoid the spikes.