Do we men even need to use conditioner?
You wash your face with a face wash and then you slap on moisturizer. You wash your hair with shampoo and guess what comes after?
Conditioner brings hair back to life after shampoo cleans the hell out of it. Hair experts and even professional good-looking people have been warning against the overuse of shampoo, recommending not to wash hair every day.
The thing is, while shampoo rids hair of dirt, it also strips it of the oils it needs. That's why it's best to supplement with a conditioner, which can return the moisture and nutrients hair requires to look and feel healthy.
The creative visualization of hair advertisements are actually correct when they portray damaged hair as a black rope covered with fish scales standing at attention and then conditioned hair as an uninterrupted strand of smooth and glossy goodness.
Quick science explanation: Those scales are overlapping cuticle cells, the external armour of hair. Hair looks gnarly when these cells don't lay flat and tight with each other, and it looks best when the cells are packed snugly together. Conditioner, through the magic of chemistry, makes cells behave. And that, my friend, is how you end up with a silky, smooth, and (amazingly) shiny mane.
If you've ever used a conditioner, you know that the effects are immediate and lasts throughout the day. An added benefit of using the good stuff is that it makes bushy hair easier to style. You'll have more success trying to look like a nonchalant Ryan Reynolds with less hair product, too.
The answer to the question is this: Unless you're trying to look like a Sleazelord on purpose, skip it. But for the rest of the population who wants that extra edge, or simply desire to feel good, take a few more minutes in the bath to condition your hair.