I work for a sub contractor and many of these issues are caused by poorly run sites. Things getting fitted when they shouldn't be and everyone knows that they are going to cause issues but we are told by the site manger to go ahead anyway. Way too many houses are rushed and things are often missed, we were one of 5 trades on site once in the morning trying to finish a plot for handover in the afternoon!
I can imagine that it's not easy. Some things, as you say, are obviously due to poorly run sites. But if you have a job to do then surely it should be done properly? Not talking about you specifically, but the people I dealt with it was like half a job was fine, as long as they could move on.
For example, it transpired that about 10cm into the grass in our garden, they'd laid concrete. They have to have at least 30 cm of topsoil suitable for cultivation there, IIRC. I dug five pilot holes to find out how extensive it was, and it was the entire garden. We didn't want to plant in the main lawn, though, so I left that (more because my other half insisted, I wanted them to do as much work as required to fix it, but there you go).
So I was told they'd be round on a Monday. Leave the gate open. I left the gate open, got home later that day and they hadn't been. Locked the gate (of course), and the next day I got a call saying, your gate is locked we can't do the work. I was like "well duh, you were supposed to come yesterday."
Rearranged the date for a week later. They did show up. I came home and had a look at what they'd done - the groundworks contractor had dug my pilot holes down to 30 cm and that was it! I was obviously unhappy and eventually it was rectified, but it's just a typical example of how they waste time doing, frankly, stupid ****.
