Even with a beam I'll hear stations off the back and sides. Granted that signals are weaker, but they are there. Often I'll have beam aimed at Europe calling CQ and get folks in Southern California answering my CQ.
So a beam isn't always the answer. Most of your transmitted signal will hopefully go in direction you're aimed. Because beams are a horizontally polarized the noise levels will be somewhat lower than those with verticals; yes, vertical antennas are more susceptible to noise. Their are advantages to verticals such as angle of radiation and ease of installation.
When I'm on the air I get the same problems everyone else has to deal with... 2 or more signals so close together neither one can be decoded ... when working a DX station people will suddenly start calling on top of the DX ... a station showing up with a wide signal that swamps out the waterfall ... and so on. We all get the same problems and have to deal with them as best we can.
Jerry n9avy #454
From: "n7we1980@... " <070@...>
Sent: Sunday, April 30, 2017 1:08 PM
Subject: Re:  Re: CE1ANF CQ'n on 20m at 20:36 zulu
Yes Joe, I hate it. On days when I'm feeling forgiving and compassionate, I remind myself that propagation is not always reciprocal and tell myself "They probably couldn't see the other station calling on frequency."
On days when I'm not too understanding (most days) I tell myself "They probably saw a weak trace but couldn't decode the call. They think if they call CQ right on the station's frequency that they will come back to them, or swing the beam, or up the power and they will bag a rare one." Then my head goes through possible descriptors - newbie, OBB (operator behaving badly) and LID - being some of the nicer ones.
I usually hang on frequency for a while in hopes I will get another shot. Most times I give up and spin the knob. Then I tell myself the only person I can control is me and vow to never do what I just saw done. Deep breaths....and on to the next QSO.
Rick - N7WE
070 - #1602