I'm at Home Depot looking at ceiling fans. Lady comes over and asks if I'm installing it or if I want them to do it. I say I'll be doing it and I've done it before. She recommends a flimsy sheet metal "ceiling fan brace". I let her know I have access to the joists from the attic and I'll be using a 2x4 brace to mount it. She lets me know the 2x4 is not strong enough and I should use her little bracket. Then she says come over here and I'll show you the demo we have setup. I let her know I've seen it and a 2x4 screwed to the 2x4 joists will be more than sufficient. She gets snippy and says ok then walks away.

I've dealt with many helpful people at HD over the years but every now and then I get one like her.