There are many things I've forgotten about my public school years. I don't remember all the presidents of the United States. I don't remember all the fights I had with my friends, and I don't remember all the lines from my first solo in choir.



What I do remember, for better or for worse, is most of what was playing on the radio at the time. I can't imagine I'm alone in defining much of my teenage years by popular music of the time. Since the majority of us hit middle school or junior high around the same time, here are some of Billboard's memory-inducing Hot 100 number one hits from 2003-2009.



"Yeah!" by Usher feat. Lil Jon & Ludacris



#1 for 12 weeks starting in February 2004



This song birthed the genre "crunk&B," coined by producer and writer Lil Jon. Usher sure knows how to bring in the ladies, and I'm sure we came running when this song was inevitably played at our junior high dances.



"Candy Shop" by 50 Cent feat. Olivia



#1 for nine weeks starting in January 2005



And so hardcore grinding was born. "I attempted to be as sexual as possible, from a male perspective, without being vulgar or obscene," 50 Cent said of the song, and I daresay he succeeded. Apparently, sex was on the brain worldwide, as this song topped the charts in a half-dozen countries.



"Hollaback Girl" by Gwen StefaniĀ 



#1 for four weeks starting in May 2005



Not only was this song catchy, but it also taught students everywhere how to spell "bananas." Those who were radio listeners may remember the 38 occurrences of cut swear words in the clean version. It takes a lot of dedication to write the same swear word into a three and a half minute song 38 times.



"SexyBack" by Justin Timberlake



#1 for seven weeks starting in Sept. 2006



This song put Justin Timberlake on the map for good. It was his first Billboard Hot #1 without the 'N Sync boys, and it also earned him Best Dance Recording at the 2007 Grammy Awards and Male Artist of the Year at the People's Choice Awards.



"Crank That Soulja Boy" by Soulja Boy Tell'em



#1 for seven weeks starting in Sept. 2007



It's almost impossible to swing both arms to one side without someone breaking into "YOU!" This song was the first ever to sell three million digital copies, now up to five million six years later. Impressive, but to put it into perspective, "Blurred Lines" by Robin Thicke sold over five million copies in its first six months alone.



"I Gotta Feeling" by the Black Eyed Peas



#1 for 14 weeks starting in July 2009



Currently holding the title of best-selling digital single ever, this song is, for many of our generation, a classic. It's what we blast at parties, when we work out and pretty much any other time. This song took the #1 spot on the Hot 100 from BEP's "Boom Boom Pow."