They seem cold and insensitive, but only at first sight. And while you are getting frustrated because they can't utter 'I love you' – maybe you should learn how to follow the signs by which they show it to you.
Capricorn
Cold and arrogant, that is the first impression of people born in this horoscope sign. They are represented by others as impenetrable fortresses that aren't touched or affected by anything, and when they process things within their own four walls, they are able to cry and weep all night. Provided that they are alone in the house, of course. Just as you break down the wall that they have built around them, another one appears and so on. Just when you are ready to give up, you will scratch their surface and you'll realize that they do have feelings and they are deep.
See also: EIGHT THINGS SMART PEOPLE OFTEN TELL THEMSELVES
Fear of getting hurt is what prevents them from showing their emotions, so they are buried deep within themselves. They would rather lose an arm than tell someone they love and care for him. However, their mask falls when you break through their walls. You only need nerves of steel and a lot of patience.
Leo
The thing that Leo can't cope with is vanity that prevents them from opening up and show their vulnerability to another person, even if they knew that person all their life. They will never admit anything they are ashamed of; you will always be under the impression that you know less about him than he knows about you. He will easily leave you hanging on, and it will be difficult for him to accept his mistake.
'Sorry' is the word that he will hardly ever say. Even if he is at some level aware that he made a mistake he will never admit it –to himself, let alone the others. In his head, he is perfect. You will pull out his tooth before you pull out the words out of his mouth that will express the feelings.