I could fill several posting boxes' worth of "sea stories," both what I experienced, observed in others, and now watch with the midshipmen we sponsor. But I will resist ...
Where else are you going to meet like-minded people in uniform, college-educated, security cleared, physically fit, with probably not too many bad/illegal habits? So, there will be your peer group, and their friends in uniform, and their civilian sisters/brothers, random meets while doing things you like and ...
Four quick vignettes:
(1) USNA sponsor son, '06, met his future wife at the plebe book issue at the end of plebe summer! There she was, a daughter of one of the staff officers wrapping up her summer job, and love bloomed right there. She was going to be a freshman at a local college, and though dating logistics are always difficult for plebes, it all worked out.
(2) Two company mates at USNA, just good friends while at USNA, ran into each other at the NEX in San Diego 4 years after graduation. Cupid strikes.
(3) Sponsor son went to do an internship at the Pentagon during summer training, met a White House intern at a briefing. They stayed in touch. Just got married last year after he finished flight training.
(4) A self-confessed computer nerd sponsor son, never comfortable with F2F socializing with new folks right at first, used match.com - though teased by friends - to great advantage, and was never without a dating relationship throughout his four years. His biggest coup was having a steady civilian girlfriend, met through match.com, who had a car, a great plus during his car-less youngster year.
There are always opportunities at the SAs, whether with fellow mids, their friends or siblings, and in Annapolis/DC/Baltimore, there is an active college-age club scene, given the number of colleges and universities in the area.
And let's not forget, there are always Mid Hounds! I will let a USNA current mid or grad explain that one.