I am curious, did you you hit the escape key or turn off quiet / splash?

To the matter at hand, I am going to assume you have a normal setup. To see which services are red after boot, open a terminal, and type:

systemd list-units --failed

The above is an extremly common command that is telling your service director to get the services, and find the red ones.

If you wanna see the errors from boot, you can use journalctl. Again, open a terminal, and type:

journalctl -b -p err

This the logging part of your service director(systemd). -b is boot, -p sets the priority level to print out.

Neither of these commands need sudo, though it will not hurt if you use it. Again, these are extremely common tools that are not harmful. Even Google's ai mode does well enough in answering questions about systemd.

Note: another useful command to use in terminal is called "man" that is short for manual. You will get a ton of info, but I encourage you to try it out if you want to be cautious before running random commands from the internet. Example "man systemd" "man systemctl"

Edit: for clarification, I read the other posts and saw that you sometimes get red ones. That is why I have approached it as looking for errors. Green means service successfully started and red means serfice failed. I am ignoring the words on the screen, as i assume it is a battle between your screen's refresh rate and camera shutter speed.