The "no" thought is not just because the path is blocked. You can be in a wide open field and still get it. What it takes is a tremendous amount of patience. You "watch wild horse" for days. Horse will still say "no" but your options change a bit. Next step is have produce, apples and carrots preferably, in your inventory. Select "feed produce". You don't go up to the horse. You just select that option and your Sim should start yelling, (calling) and waving an arm. The horse MIGHT come up to you. If it does it MIGHT show you an apple or carrot thought bubble at which point you can feed the produce and maybe even quickly select petting it's neck. Not always though. After eating the horse will hate you again. lol So it's back to "watch horse" for a bit, then another feed produce. It sometimes takes several tries of feeding produce. After days of this, (and watching the horse while it sleeps is really good, you almost always get a friend sign after that if you do not wake the horse), you'll start seeing the horse with a thought bubble with a smiling carrot or apple. This is his way of saying I'm willing to be fed. SCORE! So you feed produce. Again the no thought, but sometimes you just get a good friend thought. Now, if you want to speed up the relationship before all this nonsense, read the horse riding books and get to level 8. All the wild horses will then be much more tolerant of you and you can establish friendships and even adopt at this point.
