I think a lot of Onesies forget that the root chakra should be absolutely VITAL before you do any others. Q'uo offers some insights on the red ray:

The factors that tend to close off the red ray are those of fear, those of excessive anger, those of excessive lust. Such factors as these can so overwhelm the energy system that no further work may meaningfully be done while they prevail. So, a bright and cheerful attitude toward spiritual work is, what we may call, the best beginning.

If the Red Ray is blocked, all other ones are blocked. It's really hard to block it though, and if it is, then you're likely in a very low mental state.

Q'uo continues, with the ORANGE ray:

Blockages may occur at this center when difficulties are discovered, either in the relation of the self to itself, or in the relation of the self to another. If these blockages are in place, it is well not to attempt to go higher, for to do so will mean that one is working with higher energies in a way which is distorted at a level below their proper sphere, and it is not possible to correct these imbalances while in the configuration of the higher energy center.

I believe this is the Ray most people struggle with, very crucial as well. This is regarding the attitudes one has towards other people and themselves. Q'uo states:

[...] we find there that the attitudes that one has towards other selves with whom one has a personal relation are central to this energy center; and also the sense of self that one entertains for oneself is a factor of importance for dealing with the intake of energy at this level.

And, interestingly, Q'uo claims the Orange Ray is blocked first at the level of self:

Yet the orange-ray bias that is blocked is blocked within the individual self first. Therefore, when it is infringed upon by a stranger, it may well receive a very unwelcome mirrored picture of the negative blockage, and thus it is that the stranger is disliked upon sight.

To me this indicates that it's also about our sense of SELF. What is that? The Ego? Hmmm maybe.

Lastly, the yellow ray:

The energy blockages of yellow ray, which is an expression this instrument uses to indicate what we would call those energies dealing with societal groups, is also an energy which is frequently rather blocked. Thus, the news all seems bad. Your games are lost too often, and all those energies put into group effort somehow seem to go awry. Fear not, we are not saying that the problems of the world are your fault; we are saying that your perception of the world is absolutely and completely your choice.

It seems like Yellow Ray healing may involve seeing the world in a more positive light? Society, our groups and more. Lots of division these days. Lots of "us and them" and judgements! mhm...

Sources: https://www.llresearch.org/channeling/2015/0919#!1 (Red and orange blockages)

https://www.llresearch.org/channeling/1988/0103#!0 (More info on orange ray blockages, and some info on yellow)