Zardnaar
Legend
Id say that the biggest problem is that the dmg section quoted by @Maxperson really only applies to tier1 PCs and breaks down as players move through tier2 into tier 3 levels.
Take the monk & warlock as the prime examples designed to enable 5mwd loops. The monk has a ki pool growing equal to its levelwhile gaining a steady flow of more & more powerful abilities that also themselves often improve. That in itself is fine at earlier levels when there are likely to be more rounds of combat than the monk could spend, but it quickly topples over once the monk has enough ki to last through an encounter or two of burning it at maximum possible speed. Monk is an issue but more as an eager enabler who stands to benefit from excessive resting
The warlock is an even bigger problem getting both spell slot level scaling equal to regular casters and tend to finish a long rest with slot numbers equaling or exceeding what regular casters have of that slot level as if they are pegged to the slot count numbers of ad&d2e/3.5 casters. In tier1 & early tier2 it's not a huge deal if they squeeze in an extra rest but by the time they start the day with 2-3 4th or 5th level slots and regain them each rest it very quickly becomes obvious how lacking GM tools are when players are still expecting
the super generous rest availability of the early levels when PCs were killing rats in the basement equivalent quests
House rules to fix the absolute failure of design and outright disdain wotc has shown towards the idea of supporting GMs on the matter because players with that video game mentality who believe they are entitled to generous short rests will simply view any meaningful infringement on rest availability through house rules as evidence of stereotypical evil/killer gm behavior
@Maxperson mechanics that support the GM in limiting excess and the advice is pointless because of the reasons described above. The rest rules themselves provide extreme support in resisting a gm who is unreasonably restrictive but when it comes to the idea of players with short rest classes having an unreasonable expectation class design wotc & the ruleset itself does not even acknowledge it as possible for the players to have an expectation of excess.
Our monk essentially has unlimited focus points in effect since level 7-9 or so. 6 attacks a round.