The first of those is probably “Common Time” by James Blish.
Garrard travels around the speed of light to reach Alpha Centauri.
However, instead of experiencing the same relativistic time as his
ship, his own time passes about two hours for every second on the
ship. Movement is impossible.
The second is almost certainly “Stranger Station” by Damon Knight.
One man, out of all Sol’s billions, had the task and privilege of
enduring the alien’s presence when it came. The two races, according
to Wesson’s understanding of the subject, were so fundamentally
different that it was painful for them to meet.
Cross-referencing on ISFDB, the anthology The Arbor House Treasury of Modern Science Fiction, edited by Martin H Greenberg and Robert Silverberg and first published in 1980, contained both of those stories.
I can’t identify the third story as being in that anthology, but it could be “Bordered in Black” by Larry Niven, which has not been widely anthologised.
Two spacemen found a new planet. They observed the coastlines of all
the continents were "bordered in black" (I think it was actually an
infrared view). When they explored they found the planet had been
artificially terraformed to act as a food producing planet. All the
natural life had been exterminated and the oceans had been seeded with
some algae that would be harvested for food. But the planet had been
abandoned and the human-like caretakers had been forgotten and left
behind. The black border was the descendants of the original
caretakers who now crowded up against the beaches to get the algae
which was the only food on the planet.