I finally managed to send this work e-mail I was so reluctant to send (Basically: I know you worked hard for 2 month on this but it's not helpful and we discussed before why it wouldn't be and it's no suprise that it isn't) Sometimes it takes time to find the right tone, but the right tone can be very important especially if you potentially have to work together again.
My boss needs to have that same conversation with that persons boss and he told me today "haven't talked to him yet... I'm waiting to get into the right mood" :D I feel you!
@Virelai Looks like you have a sensible boss. That's great! I wonder how it is working in Germany. You have a reputation of being really stricts.
@Virelai Looks like a great boss.
I had the best customers in academia. You people are great!