While this is a very real possibility and something to beware of, I can also think of many very positive interactions I had where I did not always 'succeed'. The tone of the interactions I'm thinking of was not negative or competitive and I had no sense that my partner was trying to prove I couldn't do it or show off that they were better than me (and I've definitely had those interactions too so I can feel the difference!)
It felt much more like a brainstorming session. We would end up identifying weaknesses in what one or both of us were doing and often then collaborating to come up with ideas to improve the weaknesses, or if we couldn't come up with one at the moment, mulling it over later or asking Sensei about it at a later time. For me when it does work well it's more exciting or intriguing than particularly demoralizing...
I like it and agree 100% Basia. In fact more than that 1000% ha, ha. My favourite way of practice.