When I was a teenager there wasn't the predominance of STIs/STDs as there is now. HIV hadn't arrived yet, and herpes was just coming onto the scene. The only time I heard the word "chlamydia" was after being introduced to the Puerto Rican girl who lived down the block, Chlamydia Santiago. When people did happen to catch an STD, most were easily treatable with "lower level" antibiotics. It wasn't something to worry to much about. A lot of people got "clap" and it wasn't that big of a deal.
Nowadays, STDs are at epidemic levels. The CDC estimates that there are 19 million new infections every year in the United States. HIV has taken the lives of a great many people, herpes is considered a predominant STI, HPV entered onto the scene, and chlamydia is now the most reported STD in the United States. The lower level antibiotics used to treat common STDs don't work anymore, and now the CDC reports gonorrhea becoming resistant to the most powerful antibiotics used to treat it.
If you're having unprotected sex, an STD isn't something that you "may" catch, it's now something that you're "likely" to catch - and the consequences can be severe. So, now that you're aware of the dangers, the least you can do is to accept them, make wiser choices, and always use protection.
But, don't just take my word for it. See for yourself.