Don’t point out something wrong immediately
This is the hardest lesson I had to learn in my consulting work. It is is especially important if you are not familiar with the full context - which is almost never the case.The main insight for me was that yes, things can be "wrong" due to lack of knowledge or incompetence. Sometimes.But more often than not there is a good reason. Like:* we know this is stupid, but we had immense time pressure and this was the only way to get it done for the deadline; we never got the time to fix it* external system constraints (like legacy applications, legal/certification requirements, ...)* particular domain constraints that you might not be familiar with, and that only make sense if you know the details* important senior engineer X designed this and no one had the guts to call it out as flawed* the company paid a lot of money for product Y, so we just had to use it* a manager read a blog post on how technique Z is awesome, so he made us do it this way* political infighting between parts of an organisation (redundant work, refusal to work together, deliberate sabotage)* ...But you will usually not hear these reasons right away. And being critical can easily put others in a defensive stance and make it very hard to get that information at all.So my best tip is: if you spot something "wrong", don't react immediately and don't interrupt. Let the other party finish. Make a note. Gather more information. Ask why it was done this way, who is responsible, if it has been effective or not, and whatever else could be relevant.You can still be as critical as required later.