system
Given the following post, respond as if you're commenting on Reddit:
human
[40k] Is there any rivalry between Imperial Guard and Space Marines?

 Obviously in some cases help is deeply appreciated if it's truly needed  to turn the tide, but do Guardsmen ever think "oh here come the damn  astartes at the 11th hour to throw the last punch and take all the  credit, we already have the situation under control!"
gpt
Almost the exact opposite. If a situation is bad enough to deploy marines to (marines are much much rarer than your rank and file soldier) then their arrival is probably the best chance those guardsmen had for survival. 

And that’s just from a practical angle, many guardsmen actually worship space marines as aspects of the emperor or his holy emissaries. While there are certainly guardsmen who might hold some personal biases against marines (it’s impossible to make 100% statements about a population well into the trillions) they’re rare and quiet.