Whoops, I'm late to the game! Like everyone else has said, food is a great option if it works for your horse and the people interacting with him. If bringing in the horses is a routine it will be easy to add some food to make the routine more enticing. I keep a treat dispenser inside my minis' shelter and when it's time to come in at night, I fill the dispenser with a small handful of hay pellets. I used to shake the dispenser to get them running to the gate and now they wait at the gate every night before I even fill the dispenser.
If coming in is a more random event, like coming in to work, groom, vet, etc., food can still be helpful to associate catching and haltering with good things, but like others have also said, it is important that you add times of no work, no expectations too. If catching and haltering always means work on your schedule the sight of the halter does not look fun. On good days when he will allow catching, and you have no schedule, halter him then take it right off. On another day, halter him and love on him in ways he enjoys, like petting or brushing, or just sit with him in the pasture. The presence of the halter or people should not indicate work or the end of fun.
It also doesn't hurt to make work itself more enjoyable - before you exercise, train, groom, or whatever he might not find super enjoyable, start with a little bucket of hay or some loving on him. Focus on building a relationship by enjoying each other's company before getting to the nitty-gritty.
All that said, there is no arguing with a horse having a grand ol' time after being confined! My young geldings like to run laps and rough house every morning after being let out, anything I need can be accomplished a little later.
I think I could see your smile from here.
