I've never used the encounter building guidelines in the DMG until just recently. One of the things that surprised me was that I overran my daily XP budget front loading the adventuring day with one hard and one deadly encounter. Basically, the math provides you with 6 MEDIUM encounters... +1 easy encounter, if you really want to hit your max budget (Kobold Fight Club is handy for quickly calculating your budgets)
If you're going to include any hard or deadly encounters, you need to throw some easy ones in there, too, and that's where I think a lot of DMs err when trying to meet the 6-encounter quota. I feel like many DMs expect each encounter should be threatening or challenging, but the DMG encounter builder doesn't seem to think so. It appears the 'typical adventuring day' includes stomping on some mooks. I've had some easy combats resolve in less than a minute with a choice spell, and even when the PCs opt to forego resource expenditure, it's usually less than a 10 minute affair. It's... not always 'exciting,' but it's hardly a slog, and my players still take satisfaction in turning weak monsters into paste.
A point of order, an encounter doesn't have to be monsters. It can be a trap or a social challenge or whatever. Those might be good for filling out easy and medium encounters if you want actual combats to stay on the hard-deadly difficulty.