In many games, the quest design is extremely mundane and repetitive. This means that the missions, quests, or objectives that the players play through is filled with the same thing over and over. This can lead to the player getting bored of the monotonous gameplay and quitting.
For example, in almost any MMORPG suffers from this. In Blade & Soul for example, the first few missions are all "go here, then do this". One of them is "go to the beach and kill 30 crabs". Another one is "Go here and knock over 10 torches". Another one is "Go here and kill 15 wolves". This continues for the first few hours. It gets old and tired extremely quickly. It only utilizes two actions from the player: move and fight.
An additional issue with quest design can be seen in the Radiant Quest system in Skyrim. It suffers from a similar issue of producing repetitive quests that generally involve going to X location and retrieving Y item for Z character. The Radiant Quest system randomizes these various elements, in the hope that the quests will bring the players to unexplored locations.
The issue is that using quests to force the player to see the extent of a game's map is designing backwards. Ideally, the game's environment should be compelling and well-thought out enough that a player already wants to explore it. Quests should be a supplement to that base design, a way to provide rewards for the player's natural curiosity. But relying on the quests to drag a player out into a badly designed environment and badly written characters leads to those quests feeling uninspired and pointless, as the underlying meat just isn't there.
While in Skyrim there are some genuinely attractive and beautiful locations that invite the player to explore, too many feel unfinished, copy-pasted, or uninspired. After fifty dungeons fighting the same zombies in stone catacombs made of the same prefabricated parts, exploration loses its charm and the quests feel grating and pointless.
While infamous may have had some fun mechanics and some great environments, it didn't take long for the game to continue to recycle the same few missions over and over. The game took place in a city that was broken up into a few different areas that the player would eventually unlock. However once the player had beat the first area the new areas followed the same formula used in the previous ones. The enemies didn't really offer anything new but were simply more resilient. It made you feel like after passing the first area you had pretty much seen all the game was going to offer. Had new areas offered new challenges or different areas the game would have been far more interesting.
Assassin's Creed (1-Syndicate)
Assassin's is notorious for this. As to be expected that there would be a lot of missions based around killing judging by the name, however it becomes extremely repetitive. Once the player beats the first set of of different missions styles the rest become predictable. With each addition, they have come out with different themes for missions, depending on who you are contracted to help however the novelty wears off quickly and it seems to become more of a chore with each mission rather than enjoyable.
Eternal Lands Edit
Another MMO with many, many quests. While it is entirely free to play and costs nothing (though you could spend money to get a special guild map of your own put on the official server) it fails to address the quest problem. SOO many of the beginning quests are "get me X of Y". As mentioned above this greatly limits how the players can utilize their verbs and makes the scenes in the game relatively bland.
Mass Effect 1
Thought ME1's main story missions were thoughtfully designed and crafted, the game's side missions were the exact opposite. Only a handful of the planets in the Milky Way are able to be landed on by the player (aside from those hosting story missions). Once players do land on these side planets, they are presented with an ugly Perlin-noise style map with small points of interest scattered arbitrarily across them. Each planet's locations follow the same template: a crashed probe, a few mineral deposits, and a base filled with a few enemies for the player to kill and a modest reward for doing so. This lackluster side quest design isn't very interesting or rewarding to the player.