I've searched the internet and forum but can not find a solution to my problem.

I serviced my wheel bearings and hubs on my Shimano RS80 wheels. I did the front wheel first and have the bearings loaded so there is a slight amount of play but when mounted on the bike and tightened with the skewers the play is gone. The problem is they feel quite tight to turn. I moved on to the rear wheel and I have the same problem except the rear is really tight to turn. Even when I leave the bearings way too loose the wheel is still a little stiff to turn. I thought I might have applied too much grease so I took everything apart and reassembled with a very small amount of grease just to see if it would make a difference and it did not. I'm using Shimano grease. The wheels were spinning fine before I serviced them. I'm 100% sure I reassembled them correctly as its pretty obvious.

If anyone has any advise please let me know.

Thanks,

If they were fine before and they r not now then i would take it all aprt again, consult the Shimano/tech docs site and re assemble. Did you replace the bearings? and with what ?
As you say, its pretty obvious, especially the front hub.

I took everything apart again, cleaned and reassembled. Triple checked tech docs, etc., but still same problem. Even when I load the bearings so there is still some play when I tighten in the skewers the wheel does not run smooth. Its even worse when I turn the wheel backwards.

I did not replace the bearings. Since everything was running smoothly before I thought it would be best to keep the same bearings and just clean and re-grease.

I just don't know what to do?

Seems like an error you made since both wheels have the same problem.
Did you use 2 wrenches, because you need to use one to hold the cone and snug the one on the outside against it... a double nut kind of action.

The other thing is one side of the Shimano might have loose balls and other side have retainer, don't get the retainer direction mixed up but it would probably be obvious

Yes, definitely used 2 wrenches. Cone and box end.

Not sure I understand the "loose balls and other side have retainer"? I don't think there are any parts to mix up. Even the dust cap/bearing seals are not interchangeable.

The front wheel if definitely way better then the rear but I guess I just thought they would spin so smoothly after servicing. Is there any chance that the grease will somehow loosen up? Is it at all normal that they feel stiff just after servicing?

No, it's not normal. Something's wrong.