Fact 1: You don't need an agent to approach a publisher, and you don't need an agent to be published. However, most publishers won't look at unsolicited manuscripts. If they do, be prepared for a long, long wait. Or for your manuscript to be looked at by someone on work experience.
Fact 2: It is NOT an agent's job to carefully read every unsolicited manuscript that comes in through the door.
Fact 3: An agent's job is to look after existing clients and their work. That's why authors like having agents; they don't want to have to read the small print, or negotiate, or invoice or do any of the hundreds of things agents do for clients.
Fact 4: Every agent wants to discover a brilliant new talent, but just because you've written 100,000 words it doesn't automatically follow that they're brilliant.
Fact 5: Every agent gets fed up with badly written, rude, demanding, illiterate letters
Fact 6: Every agent sees far too many of the above
Fact 7: Every agent receives hundreds of manuscripts to look at a year - for some it may be thousands - and can rarely take on more than a couple of new clients in each year
Fact 8: The maths of Fact 7 means your work may be above average, it may even be rather good, but only exceptional work will get taken on.
Fact 9: It is your job to make your work exceptional, not the agents.
Fact 10: New writers are taken on by agents every year.
I'll write about how to make your work exceptional tomorrow.