Years ago when I wrote code or programs if you like? Memory and hard drives were seriously small, that is capacity was so limited that programs had to be written as accurate as can be and 'packaged' as tightly as possible, nowadays with copious amounts of memory/hard drives all faster than ever it seems that programs are written a little more shall we say.....with a little less care, the packaging less tidy, so just the slightest change can cause all sorts of problems, some easy to 'see' and just as easy to sort however, some errors/modifications can cause absolute carnage.