People that are forced to work under AGILE/SCRUM already heard it.

We work together therefore we increase the competence and speed up development. IT IS NOT!

• When you combine a high experienced developer in a group of less experienced one developers then the experienced will always find flaws. At first that will contribute to the team and make projects a success. But over longer terms the experienced developer will always be better and it will depress the less experienced developers.
• If you develop in daily SCRUM tasks then you will develop bad code. You simply don't get the time to cleanup up the code you just created. This is very depressing because the next guy that takes over your job will find buggy code and think that you are an complete idiot. This will cause friction in the team.
• If you are an experienced developer then you will develop in guaranteed ways to get good code. But less experienced developer will freak out because you are doing things they never learned in school. They will think you are an idiot and correct your mistakes. In turn you will call them an idiot because they made the code worse and buggy. In the end a team fight.
• Pair programming will speed up your code you produce but it also induces a knowledge war. Both pair developers will wear each other out in the end and both will jump from a tall building.

Now for all those AGILE/SCRUM masters that keeps on defending their religion and claims that it works for them. It only gives the illusion that it works because you have only the worst developers in your team left. You have lost any metrics to verify how good your team really is.

Code review is interested but do this much later until the original developer had a chance to clean it up. OR when he is ready.

A code review is literally an exam every single day by your complete team. That induces stress like it was your last exam in school every single day.