Space payloads usually cost tens or hundreds of millions of dollars and their loss can be a huge setback for their operators. Launcher reliability is often quoted in excess of 99.9%; that might sound excellent but any failure is problematic.
To get a reasonable fraction of the lift off mass into orbit, the systems, particularly the engines, have to be run close to failure. There is little margin for faults in either manufacture or assembly.
On 4 July, the 13th Electron mission from Rocket Lab failed after first-stage separation. The rocket was carrying an experimental imaging satellite built by Canon,