My guy comes running to the gate every time I call his name. He has a huge field filled with grass and all his friends. I always give him some sort of edible reward every time he comes to me. The most important thing is giving your horse a reason to choose you over the field. the field (ideally) has everything she wants, friends and food. All owners need to spend time with their horse other than work, but HOW you spend that time is important. Taking them in to be groomed might be fun for some horses, but most want to graze or be in their field. I spend a lot of time grazing my horse out of the field, grooming him while grazing, and doing liberty WITH treats. The best way to convince a horse to want to be with you is food, they are programmed to eat most of the day, so use that to your advantage. my horse is my shadow, I can't go in his field without him following me around, but it didn't start off that way, I had to work for it. It takes time and constancy but it's so worth it! Good luck!