Here's why I love the Abjuration wizard.
1. The Concept
In a world where literally everyone and their next door neighbor is a magic-user of some sort, anti-magic is extremely useful and powerful. Even the most powerful lich, mummy lord, and archmage will start hoarding their Reactions and spell slots as soon as you walk into the room. You can save the party countless debilitating effects and hundreds of points of damage with a single, well-timed Counterspell. Breaking curses, scrubbing invisibility from pesky rogues, shutting down magic items, it's all in your wheelhouse.
Abjuration spells don't often allow save throws, and are rarely subject to resistance and immunity, so your magic is almost always at full-strength no matter what you're fighting.
And nothing beats the feeling of successfully Counterspelling your DM's Meteor Storm. The thunderous cheer from your friends at the table, the sour hate-filled look on your DM's face...seriously, I needed a cigarette afterward.
2. The Arcane Ward
Every time you cast an Abjuration spell, you gain a buffer of protection that scales with your level and the spell level. So not only do you protect the party from incoming fireballs and invisible rogues, you replenish your own temp hit points in the process. Eventually you learn to share this forcefield with allies within 30 feet.
3. Spell-breaking
Counterspell is arguably one of the most powerful spells in the game, and it gets even easier at 10th level (you get to add your proficiency bonus to opposed caster level checks when you cast it, or when you cast Dispel Magic.) This has good synergy with your arcane ward, too, since spending that higher spell slot is now less risky and gives your Arcane Ward more juice.
Abjuration wizards are the best wizards.
Change my mind.