A surprisingly unique and down-to-earth slice of life. If you can relate to Tomoko Kuroki as a character, or the misfortunes that she goes through in one way or another, this manga will also be quite a sentimental callback to your high school days.
Most aspects in this manga are pretty true to life and beautifully executed, especially the characters and how they develop individually. The plot gets better overtime, and the pacing feels natural. Though what I adore about this manga is the relationship between the characters - Tomoko's and Yuri's exchange in Chapter 136 is easily one of the most wholesome and genuine interaction I have ever seen in a manga.
The manga never fails to deliver from start to a certain volume, where Tomoko pretty much got sidelined in her own manga. This in itself isn't bad, but almost all the other characters started to have their trope and quirk stereotyped to the max, just for a cheap attempt to reproduce the cringe comedy of the first chapters. An arc that lasted for about 2 years was also introduced, which ruined the general pacing of the manga, but I would say it is not that bad. Tomoko's personality doesn't do an 180 just because she has some friends. Her degeneracy is, and will always be an adored and deplorable part of her, which I found to be reflected faithfully in that arc.
Overall, WataMote is a beautiful story about a socially anxious girl finding herself some fulfillment and a purpose in life, all disguised as a cringe comedy. There are some low points, sure, but it's definitely a manga you will not regret reading.