Gate C? Gate 3?!!!

Flying back to home today. I am now at Phoenix Sky harbor International Airport, reached here at 11am. My flight schedule is @327pm, mmmm..you may curious why I have to come to the airport so early? The reason is because I was sharing the same cab with my Israel colleague. His flight is at 1pm.. actually I'm OK to be here early, no harm waiting here. You know, when I was checking in, the flight information on the monitor screen were showing the gate will be located at Gate C. Thus I've directed my way to Gate C and sitting there.., surfing net and waiting for boarding. Mmm.. while sitting there for about 1 hour 30mins, I started feel weird, why there is no body here and was so damn quiet? No, no! I decided to walk away from here and re-confirm the gate information. Guess what?! The gate number has been changed from C to 3, without any announcement.. my God! I might miss the flight to LA if I didn't verify the information. So, never trust to the screen information and it may be altered from time to time, just have to be more caution, especially when we travel alone. Verify and check again!