Are daddy long legs spiders DANGEROUS?? I have some in my room and I see them but don't kill them?

No, all three critters known as daddy long legs are considered totally harmless.
I will start with the cellar spider,AKA daddy long leg spider. A myth these spider have lethal venom but can't bite is wrong on both counts. they can indeed bite, but their venom is very mild, likely having no effect on humans at all,their fangs are so small, likely a bite from on would go completely unnoticed.
Cant fathom how many cellar spiders I have handled and as yet, never been able to provoke one to bite.
Next on the list is the Opilions AKA harvestman,AKA grandaddy longlegs. These arachnids are close cousins to spiders, but not true spiders. They produce no venom, make no web, and not known to bite.
Daddy long legs, not annexing the "spider" distinguishes these from their cellar spider counterpart.
Often called granddady longlegs, as some species can have a 9 inch legspan.
The last critter known as daddy longlegs is a flying insect, the crane fly. These harmless insects lack a biting mouth part and have no stinger, again, totally harmless.
Your little friends, are worth having a few about as they prey on any bug sort they can trap in their web, even something like the black widow spider. It is your call to welcome them, I do. If they just seem to be in great numbers, that can make them a pest and if neglected can be infestive, time to thin the herd a bit.
These are the most common house spider worldwide, if they were any problem, you would hear about it.
I think they are sort of a cool spider, very gently touch one and watch it gyrate in its web, they also have the moniker vibrating spider. Some people perceive them as scary or repulsive, to me they are like little pets. their worst might be a messy web.
https://www.youtube.com/watch?v=dudlGvVhsXQ
https://www.youtube.com/watch?v=pin3BrTjW2g
( in the event you should handle these, be very careful, their legs are very delicate and break easy.)

Mythbusters pretty much debunked that they are dangerous.
http://www.discovery.com/tv-shows/mythbusters/videos/daddy-longlegs-minimyth/

No, they cannot harm you.
And they are not true spiders. They are harvestmen. They are arachnids but not spiders.
Though some people call crane flies daddy-longlegs too. But they are insects and have wings. These are harmless too. They look like giant mosquitoes, but they are not.

No they're harmless bur still scary looking lol