Disruption of the sequence of automatically increasing identity ID numbers

[Mistaismyfav]

Hello; I have a SQL database on my local machine. I have written a program in C# for adding data to the database and performing data retrieval operations. However, I want the database IDs to increment one by one continuously. When I insert data, for example 33-34-"1001", the sequence gets disrupted. What could be the reason for this issue?