One of these quirks is cheapness.
This was one of the first 'unknowns' that I discovered after marriage. I never really knew it before hand because we didn't live together, and he only visits his frugality on himself. With me and other loved ones, he's more than generous. But with himself, he couldn't be tighter.
He loves nothing more than to put on an ugly shirt and say "see this shirt? Nineteen ninetyfive." He's not talking about the price, folks. That's the year he got the shirt.
This man has no shame when it comes to holding on to money.
The piece of paper in front of the bad mango is a note from him to me, reading "DO NOT THROW AWAY." Why not throw away a bad piece of fruit? Because he planned to return it to the grocery store and get his dollar fifty back. (If you're curious about the monster in the refrigerator, you can read about it here.)
Another facet of his cheapness is an intense affection for change. He delights in paying for purchases with coins. This was the source of much friction when we were newlyweds. Now he warns me ahead of time so I can hide while he's counting nickels with ten people behind him in line at WalMart. When the cashier acts annoyed, Mike says in his Ugandan accent "I understand this is United States currency. Is that accurate?" This makes me smile every time (from my hiding place of course).
What quirks do you love about your mate?