I personally will react negatively for about 5 to 15 minutes to any new large change idea so I just work to make sure I don't make judgments during that window. It does however let me get into real issues with the idea pretty quickly.
I will often just tell people okay that's a big change give me time to go through the five stages of grieving and I think we'll be good
That's awesome - sounds like you have an amazing degree of introspection: you understand what you are like and you know how to manage through that.
Btw one reason companies ask interviewees about their weaknesses is not because the answer matters but because it shows whether a person thinks about what they are like, or not. Eg if someone ever said what you said "one of my weaknesses is that I freak out in the first 5 mins but I learned to work around that" - a real green flag that you are an excellent person to work with.
I will often just tell people okay that's a big change give me time to go through the five stages of grieving and I think we'll be good